Request for Recipe (.223 77gr HPBT), also info to share

[phish]

I'm wondering if it's easier to achieve Mk262 speeds with a 1:8 SPR barrel, such as the one from CMMG. As long as the twist is really an 8, it should stabilize the 77 grain bullet from Sierra, Nosler, or Berger.

[ocabj]

From what I understand, you will generally get faster MV out of a faster twist barrel.

[phish]

This is probably an oversimplification, but the inverse is probably true because the bullet is spun by a shorter length of lands.

If you take the lands from a 1:7 twist barrel and stretch them out straight, they'll be longer than a 1:8 twist barrel of equal length. The bullet has to travel the same distance in terms of barrel length, but it has a longer length of rifling to pass through with a faster twist barrel.

Pressures are mostly equated as being higher in a faster twist, perhaps that's why higher speeds are expected, but it puts more stress on the brass. I wouldn't be surprised if Mk262 cases won't have the same amount of reloads when compared to XM193 cases.

Of course, a lot things like powder, primer, chamber dimensions, etc. come into play.

I don't know if the plane will take off or not...

[ocabj]

I can't remember where I read it, but it was stated that faster twist usually results in faster MV.

My competition gun uses a 1 in 7" and my practice gun is a 1 in 8" twist. With the same load, the 1 in 7" has a MV of 2730fps and the 1 in 8" has a MV of 2675. But, it's possible that the lower MV is impacted by the higher round count in the 1 in 8" gun, the difference in barrel material, and possibly even the chambers.

[Jicko]

Originally Posted by ocabj

I'm nearly positive that the powder charge weights you'll use to achieve Mk262 muzzle velocities in your handloads will be above the maximum data listed in every published data book out there.

Definitely!! Mk262 rounds, by design, are for 5.56 NATO chamber..... it would definitely be dangerous if anyone is blindly using the information from this thread instead of working it up for their particular chamber/rifle combo. I'm just trying to document my process, and give you guys some references, info, and starting points.

Most, if not all, published databook out there will give you SAMMI 223 parameters.

Originally Posted by ocabj

Frankly, the more I played with my own MK262 experiments, I came to the realization that it wasn't a very optimal round as far as accuracy is concerned. If you think about it, Mk262 was designed to give enough power to the bullet out of barrels as short as 14.5". I don't have a 14.5" barrel, but if you apply the theoretical 50fps per 1" rule, a 14.5" barrel will give a MV of around 2625fps. 2650-2750 is about the sweet spot for the 77gr.

I'd be willing to bet that commercial/SAAMI 77gr BTHP muzzle velocities will result in better accuracy in an 18" SPR barrel than MK262 muzzle velocities. And even more so out of a 20" barrel.

There is certainly an underlying reason for MK262 being developed as a "anti-personel battle round" rather than a "benchrest match round". My *little* experiment / R&D here is just a project with a certain goal, after I've done this.... I may go back, and start another project to "find the most accurate" recipe...

So, guys... stay tuned...

[dw1784]

JR, thanks for the updates.
I do have the "ring" you're referring to but not to the degree of damage as seen in the close-up photo.

Wondering if the case mouth dia on that batch of brass is smaller than spec? are you loading straight from the pkg with no case prep(copper shaving from no ID chamfer)? I am using Golden West once-fired LC brass and I notice they are sized on the "smaller" side as seen with my Wilson gage. I sample case length every few pieces and chamfer OD then ID making sure there's no sharp edges to cut into the jacket material.

Keep us updated as I've learned quite a lot from your experiment

[Jicko]

They are sized. Once-fired "Fed 223 Rem" cases from AE223s.

I didn't chamfer the case mouth originally. But even if I do, I just get rid of most of the "copper shaving" problem.... yet not fixing the "ogive ring mark" issue.

Originally Posted by dw1784

JR, thanks for the updates.
I do have the "ring" you're referring to but not to the degree of damage as seen in the close-up photo.

Wondering if the case mouth dia on that batch of brass is smaller than spec? are you loading straight from the pkg with no case prep(copper shaving from no ID chamfer)? I am using Golden West once-fired LC brass and I notice they are sized on the "smaller" side as seen with my Wilson gage. I sample case length every few pieces and chamfer OD then ID making sure there's no sharp edges to cut into the jacket material.

Keep us updated as I've learned quite a lot from your experiment

[supersonic]

will a 1/9 even stabilize a 77gr. HPBT?

[Jicko]

Originally Posted by supersonic

will a 1/9 even stabilize a 77gr. HPBT?

General believe, theoretically speaking, most likely...... NO. But you can try on your particular rifle, YMMV, and some had shot 77gr HPBT out their 1x9 (some are not really 1x9 but somehow being 1x8something) and find it OK.

But, if you have a choice... get 1x8 or 1x7 barrel, if you ever think of having a chance to shoot 77gr rounds.

If you aready have a 1x9 barrel, you better stick with 69gr max....

[Jicko]

I think I finally solved my "ogive ring marking" (and case mouth copper shaving) problem of my Dillon RL500B.

For the "case mouth copper shaving" problem, I think once I freed up the "carbide expander ball", that pretty much took care of it. My "carbide expander ball" inside the deprime pin of my Dillon sizing die was "over tighten" and "locked" down. I need to *slightly* loosen the deprime pin, and that free the "ball". According to Dillon's tech-support, the "ball" will center itself and expand the case mouth appropriately.

For the "ogive ring marking" problem, I ended up having to use this Dremel's "84922 Silicon Carbide Grinding Stone" bit to *open* up the bullet seating stem inside my Dillon seating die. So happened that the shape and angle of this bit match quite perfectly with the Nosler 77gr bullets that I am using. I finish the surface up wet sanding with some high grit sand paper (just slightly). I basically custom shaped the inside of the seating stem to hold onto the bullets. The end result is... NO MORE "ring markings"!! Hurray!!



PS. I'll soon post an update with the last chrono results of a batch of "fixed" 24.5gr of RL15 getting to 2800fps avg. (probably due to warmer weather??)

PPS. I also found out that I am "lucky" that my 24" 1x9 SS Bull Barrel can actually stablize these 77gr Nosler HPBT!! I have only so far did a couple of rounds, I will be extensively testing this later.

[ar15barrels]

Cartridge          : .223 Rem.
Bullet             : .224, 77, Sierra HPBT MatchK 9377
Cartridge O.A.L. L6: 2.250 inch or 57.15 mm
Barrel Length      : 18.0 inch or 457.2 mm

Predicted Data for Indicated Charges of the Following Powders.

Matching Maximum Pressure: 55000 psi, or 379 MPa

or a maximum loading ratio or filling of 105 %

These calculations refer to your specified settings in QuickLOAD 'Cartridge Dimensions' window.
C A U T I O N : any load listed can result in a powder charge that falls below minimum suggested
loads or exceeds maximum suggested loads as presented in current handloading manuals. Understand
that all of the listed powders can be unsuitable for the given combination of cartridge, bullet
and gun. Actual load order can vary, depending upon lot-to-lot powder and component variations.
USE ONLY FOR COMPARISON !

36 loads produced a Loading Ratio below user-defined minimum of 80%. These powders have been skipped.

Powder type          Filling/Loading Ratio  Charge    Charge   Vel. Prop.Burnt P max  P muzz  B_Time
                                      %     Grains    Gramm   fps     %       psi     psi    ms
---------------------------------  -----------------------------------------------------------------
IMR 3031                           100.0     23.1     1.49    2730   100.0    55000   11635   0.952  ! Near Maximum !
SNPE Vectan SP 11                  105.0     26.1     1.69    2721    96.1    54711   12715   0.948  ! Near Maximum !
IMR 4895                           101.7     24.0     1.55    2718    98.0    55000   12096   0.937  ! Near Maximum !
Winchester 748                      94.1     24.4     1.58    2718    98.5    55000   12120   0.950  ! Near Maximum !
Alliant Reloder-15                 102.0     24.6     1.59    2702    95.8    55000   12375   0.959  ! Near Maximum !
Accurate XMR 2495                  101.1     23.3     1.51    2702   100.0    55000   11505   0.990  ! Near Maximum !
Accurate No.2520                    96.0     24.7     1.60    2699    99.0    55000   11911   0.968  ! Near Maximum !
SNPE Vectan Sp 7                   101.9     26.3     1.70    2698    95.8    55000   12424   0.956  ! Near Maximum !
Hodgdon BL-C2                       94.8     24.9     1.61    2692    97.7    55000   12133   0.963  ! Near Maximum !
Vihtavuori N150                    102.9     24.5     1.59    2692   100.0    55000   11409   0.958  ! Near Maximum !
IMR 4320                           100.4     24.6     1.59    2686    96.1    55000   11927   0.944  ! Near Maximum !
Hodgdon H335                        91.4     23.9     1.55    2684    98.9    55000   11679   0.956  ! Near Maximum !
Ramshot TAC                         94.8     24.0     1.55    2679    97.8    55000   11785   0.958  ! Near Maximum !
Accurate XMR 4064                  105.0     24.5     1.59    2679    99.5    53112   11959   1.001  ! Near Maximum !
SNPE Vectan SP 9                    99.0     24.7     1.60    2679    96.3    55000   11985   0.956  ! Near Maximum !
Hodgdon H322                        91.8     22.1     1.43    2678    99.8    55000   11080   0.953  ! Near Maximum !
SNPE Vectan SP 10                   88.8     22.9     1.48    2675    99.4    55000   11366   0.961  ! Near Maximum !
Vihtavuori N135                    102.8     23.7     1.54    2671   100.0    55000   10900   0.964  ! Near Maximum !
Vihtavuori N550                    105.0     26.4     1.71    2667    93.2    50994   12827   0.983
Ramshot X-Terminator                89.7     22.4     1.45    2667    99.7    55000   11103   0.962  ! Near Maximum !
Accurate No.2460                    94.2     23.9     1.55    2657    98.5    55000   11434   0.977  ! Near Maximum !
Winchester 760                     105.0     26.7     1.73    2657    89.5    51389   12711   0.975
Hodgdon VARGET                      98.4     23.8     1.55    2656    96.4    55000   11578   0.954  ! Near Maximum !
IMR 4064                           101.2     23.9     1.55    2656    95.8    55000   11576   0.957  ! Near Maximum !
Vihtavuori N140                    101.2     23.9     1.55    2656    99.6    55000   11068   0.960  ! Near Maximum !
Ramshot BigGame                    105.0     25.5     1.65    2649    94.9    50238   12363   0.986
Accurate No.2230                    91.5     23.5     1.52    2646    98.4    55000   11202   0.973  ! Near Maximum !
Alliant Reloder-12                  94.2     23.2     1.50    2646    99.8    55000   10830   0.959  ! Near Maximum !
Alliant Reloder-10x                 86.7     20.9     1.35    2646   100.0    55000   10309   0.970  ! Near Maximum !
Accurate XMR 2015                   96.9     21.8     1.41    2634   100.0    55000   10315   0.976  ! Near Maximum !
Hodgdon H414                       101.9     26.4     1.71    2633    86.6    55000   12065   0.964  ! Near Maximum !
Vihtavuori N540                     99.3     25.0     1.62    2631    96.4    55000   11523   0.965  ! Near Maximum !
Accurate 2200                       83.6     21.3     1.38    2627    99.0    55000   10616   0.959  ! Near Maximum !
Hodgdon Benchmark                   94.4     22.5     1.46    2624    98.4    55000   10844   0.962  ! Near Maximum !
Vihtavuori N133                     96.0     22.1     1.44    2610   100.0    55000    9976   0.962  ! Near Maximum !
IMR 4198                            88.3     19.7     1.27    2609   100.0    55000    9471   0.953  ! Near Maximum !
Hodgdon H4895                       97.2     23.2     1.50    2604    96.7    55000   10786   0.960  ! Near Maximum !
Vihtavuori N130                     91.3     21.3     1.38    2598   100.0    55000    9748   0.969  ! Near Maximum !
Hodgdon H4198                       89.3     19.9     1.29    2593    99.7    55000    9804   0.955  ! Near Maximum !
Ramshot Hunter                     105.0     27.0     1.75    2593    89.2    47768   12482   1.008
Hodgdon H380                       105.0     26.1     1.69    2579    87.5    49685   11973   1.006
Accurate No.2700                   102.7     26.1     1.69    2576    89.4    55000   11047   0.971  ! Near Maximum !
Vihtavuori N120                     85.8     19.6     1.27    2555   100.0    55000    8733   0.973  ! Near Maximum !
Alliant Reloder- 7                  80.0     18.9     1.22    2550   100.0    55000    8889   0.996  ! Near Maximum !
IMR 4227                            83.4     18.1     1.17    2549   100.0    55000    8679   0.958  ! Near Maximum !
Hodgdon H4227                       81.8     17.7     1.15    2539   100.0    55000    8458   0.963  ! Near Maximum !

[ar15barrels]

Cartridge          : .223 Rem.
Bullet             : .224, 77, Nosler HPBT 22421
Cartridge O.A.L. L6: 2.250 inch or 57.15 mm
Barrel Length      : 18.0 inch or 457.2 mm

Predicted Data for Indicated Charges of the Following Powders.

Matching Maximum Pressure: 55000 psi, or 379 MPa

or a maximum loading ratio or filling of 105 %

These calculations refer to your specified settings in QuickLOAD 'Cartridge Dimensions' window.
C A U T I O N : any load listed can result in a powder charge that falls below minimum suggested
loads or exceeds maximum suggested loads as presented in current handloading manuals. Understand
that all of the listed powders can be unsuitable for the given combination of cartridge, bullet
and gun. Actual load order can vary, depending upon lot-to-lot powder and component variations.
USE ONLY FOR COMPARISON !

36 loads produced a Loading Ratio below user-defined minimum of 80%. These powders have been skipped.

Powder type          Filling/Loading Ratio  Charge    Charge   Vel. Prop.Burnt P max  P muzz  B_Time
                                      %     Grains    Gramm   fps     %       psi     psi    ms
---------------------------------  -----------------------------------------------------------------
IMR 3031                           100.0     23.1     1.49    2730   100.0    55000   11629   0.952  ! Near Maximum !
SNPE Vectan SP 11                  105.0     26.1     1.69    2720    96.1    54686   12706   0.948  ! Near Maximum !
IMR 4895                           101.7     24.0     1.55    2718    98.0    55000   12089   0.938  ! Near Maximum !
Winchester 748                      94.1     24.4     1.58    2718    98.5    55000   12114   0.950  ! Near Maximum !
Alliant Reloder-15                 102.0     24.6     1.59    2702    95.8    55000   12368   0.959  ! Near Maximum !
Accurate XMR 2495                  101.2     23.3     1.51    2702   100.0    55000   11499   0.990  ! Near Maximum !
Accurate No.2520                    96.0     24.7     1.60    2699    99.0    55000   11904   0.968  ! Near Maximum !
SNPE Vectan Sp 7                   101.9     26.3     1.70    2698    95.8    55000   12417   0.956  ! Near Maximum !
Hodgdon BL-C2                       94.8     24.8     1.61    2692    97.7    55000   12127   0.963  ! Near Maximum !
Vihtavuori N150                    102.9     24.5     1.59    2692   100.0    55000   11404   0.958  ! Near Maximum !
IMR 4320                           100.4     24.6     1.59    2686    96.1    55000   11920   0.944  ! Near Maximum !
Hodgdon H335                        91.4     23.9     1.55    2685    98.9    55000   11673   0.956  ! Near Maximum !
Ramshot TAC                         94.8     24.0     1.55    2680    97.8    55000   11778   0.958  ! Near Maximum !
SNPE Vectan SP 9                    99.1     24.7     1.60    2679    96.3    55000   11978   0.956  ! Near Maximum !
Accurate XMR 4064                  105.0     24.5     1.59    2679    99.5    53085   11952   1.002  ! Near Maximum !
Hodgdon H322                        91.8     22.1     1.43    2678    99.8    55000   11074   0.953  ! Near Maximum !
SNPE Vectan SP 10                   88.8     22.9     1.48    2675    99.4    55000   11360   0.961  ! Near Maximum !
Vihtavuori N135                    102.8     23.7     1.54    2671   100.0    55000   10894   0.964  ! Near Maximum !
Ramshot X-Terminator                89.7     22.4     1.45    2667    99.7    55000   11097   0.962  ! Near Maximum !
Vihtavuori N550                    105.0     26.4     1.71    2667    93.2    50969   12817   0.984
Accurate No.2460                    94.2     23.9     1.55    2657    98.5    55000   11428   0.977  ! Near Maximum !
Winchester 760                     105.0     26.7     1.73    2657    89.5    51365   12701   0.976
IMR 4064                           101.2     23.9     1.55    2656    95.8    55000   11569   0.957  ! Near Maximum !
Hodgdon VARGET                      98.4     23.8     1.54    2656    96.4    55000   11569   0.954  ! Near Maximum !
Vihtavuori N140                    101.2     23.9     1.55    2656    99.6    55000   11062   0.960  ! Near Maximum !
Ramshot BigGame                    105.0     25.4     1.65    2648    94.9    50217   12355   0.986
Accurate No.2230                    91.5     23.5     1.52    2646    98.4    55000   11196   0.973  ! Near Maximum !
Alliant Reloder-12                  94.2     23.1     1.50    2646    99.8    55000   10824   0.959  ! Near Maximum !
Alliant Reloder-10x                 86.7     20.9     1.35    2646   100.0    55000   10303   0.970  ! Near Maximum !
Accurate XMR 2015                   96.9     21.8     1.41    2634   100.0    55000   10310   0.976  ! Near Maximum !
Hodgdon H414                       102.0     26.4     1.71    2634    86.6    55000   12058   0.965  ! Near Maximum !
Vihtavuori N540                     99.3     25.0     1.62    2631    96.4    55000   11517   0.965  ! Near Maximum !
Accurate 2200                       83.6     21.3     1.38    2627    99.0    55000   10610   0.959  ! Near Maximum !
Hodgdon Benchmark                   94.4     22.5     1.46    2625    98.4    55000   10839   0.962  ! Near Maximum !
Vihtavuori N133                     96.1     22.1     1.43    2610   100.0    55000    9971   0.962  ! Near Maximum !
IMR 4198                            88.3     19.7     1.27    2609   100.0    55000    9466   0.953  ! Near Maximum !
Hodgdon H4895                       97.2     23.2     1.50    2604    96.7    55000   10780   0.960  ! Near Maximum !
Vihtavuori N130                     91.3     21.3     1.38    2598   100.0    55000    9743   0.969  ! Near Maximum !
Hodgdon H4198                       89.3     19.9     1.29    2593    99.7    55000    9799   0.955  ! Near Maximum !
Ramshot Hunter                     105.0     27.0     1.75    2592    89.2    47746   12473   1.008
Hodgdon H380                       105.0     26.1     1.69    2578    87.5    49661   11963   1.007
Accurate No.2700                   102.8     26.1     1.69    2576    89.4    55000   11040   0.971  ! Near Maximum !
Vihtavuori N120                     85.8     19.6     1.27    2555   100.0    55000    8728   0.973  ! Near Maximum !
Alliant Reloder- 7                  80.0     18.9     1.22    2551   100.0    55000    8885   0.996  ! Near Maximum !
IMR 4227                            83.4     18.1     1.17    2549   100.0    55000    8674   0.959  ! Near Maximum !
Hodgdon H4227                       81.8     17.7     1.15    2539   100.0    55000    8455   0.962  ! Near Maximum !

[ar15barrels]

Over two days and no comments on this data?

[Prc329]

That info was very helpful in my own development. Helped me decide on a powder to start with.

[Jicko]

Originally Posted by ar15barrels

Over two days and no comments on this data?

Thanks for those numbers.... I have been busy and there hasn't been more numbers and data points "yet"..... soon, I'll have some updates...

[ETD1010]

sweet. I started loading 75 grain OTMs at 24.0 gr. so it looks like I'm on the right track... but until I get a chrono... I'm not sure if I wana push it to that 24.4 limit. . .

[MrLogan]

Wow, this is great info!

[Prc329]

This info was very helpful in developing for my bolt gun. Thanks.

[XXX]

Bolt2Bounce...Looks like you have had some success with WC 846. I also shoot some high power matches and wanted to know if you had any other recipes for 846 with possibly Sierra 69's or 80's. Thanks for you help.

[pottymouth310]

anyone know anyplace here in LA that sells chronographs?

thanks,

[jandmtv]

turners might.

[Jicko]

FYI.

I was doing some further testings this past weekend.

I found that primers DO affect velocities!! Significantly!! I never thought that it would be THIS significant.

Nosler Custom Comp 77gr HPBT
Chrono @ 12ft, Temp 60F
5 rounds avg, shot from 18" Mk12Mod1

24.8gr RL15, 2.25 OAL, LC06 cases
CCI #41 yields 2738 fps, ES 73/SD 28.2
CCI BR4 yields 2699 fps, ES 34/SD 16.3

25.3gr VARGET, 2.26 OAL, LC06 cases
CCI #41 yields 2767 fps, ES 89/SD 34.2
CCI BR4 yields 2707 fps, ES 33/SD 15.6

[1911su16b870]

From the Sierra Website:

.223 Loading Data for Sierra's 77 grain HPBT MatchKing

http://www.sierrabullets.com/index.c...ssue=3#loaddta

[Jicko]

There is a HUGE discrepency between this http://accurateshooter.net/Downloads/sierra223ar.pdf (please look at page 222) and your link!!!!!!!!!

The test spec (the firearm and components used) seems to be the same, but the data are VERY VERY different!!!!

On page 222 of the 5th edition reloading manual http://accurateshooter.net/Downloads/sierra223ar.pdf
(eg. 24.1gr of RE15 yields 2600fps)

VS

Page 1 of the X-Ring bulletin
http://www.sierrabullets.com/techser...ve/vol6no3.pdf
(eg. 24.1gr of RE15 yields 2750fps)


I wondered why!!!!!! I'm writing them an email!!!!!!

Originally Posted by 1911su16b870

From the Sierra Website:

.223 Loading Data for Sierra's 77 grain HPBT MatchKing

http://www.sierrabullets.com/index.c...ssue=3#loaddta

[ar15barrels]

Originally Posted by Jicko

There is a HUGE discrepency between this http://accurateshooter.net/Downloads/sierra223ar.pdf (please look at page 222) and your link!!!!!!!!!

The test spec (the firearm and components used) seems to be the same, but the data are VERY VERY different!!!!

I wondered why!!!!!!

Differences in barrels can account for 100fps or more difference with the same load.

[Jicko]

Originally Posted by ar15barrels

Differences in barrels can account for 100fps or more difference with the same load.

I understood that part, but BOTH quoted the SAME test spec

Originally Posted by X-Ring bulletin

Test Specifications
Firearms used: Colt AR-15A2 HBAR
BBL Length/Twist; 20"/1x7"

Test Components
Cases: Remington
Trim-to Length: 1.750"
Primers: Remington 7 1/2

EXCEPT that the reloading manual quote "Federal" cases vs "Remington" cases for the X-Ring bulletin. I don't think changing cases will yield 150fps diff!!!!!!

[wildcard]

Originally Posted by Jicko

I understood that part, but BOTH quoted the SAME test spec



EXCEPT that the reloading manual quote "Federal" cases vs "Remington" cases for the X-Ring bulletin. I don't think changing cases will yield 150fps diff!!!!!!

I've never chronoed using different brands of cases.. but i'll tell ya it sure makes a hell of a lot of difference in POI. Talking about 2 MOA last time I tested.

[Jicko]

BTW, I don't think 24.1gr of RE-15 will get you 2750fps with a 20" barrel.

[Timberwolf]

Every thing in the equation impacts velocity, POI/POA etc.

Different barrels will shoot the same load to different velocities, and atmospheric conditions play into that as well.

Different cases impact it due to different case capacities, and different primers, like different powders, have different burn rates.

This is why during load development you try for as many constants as possible and why the change of just one component in the mix will send you back to the drawing board.

[1911su16b870]

Jicko, I currently am shooting the 69-gr SMK HPBT and 75-gr TAP, but was looking up Sierra's bullet lengths for some stability calcs I was doing. I saw the info and figured I post it here as on topic. Sorry for the discrepancy? Maybe call Sierra tech services? allways wanted to use this smilie, I guess this is the place...

[Jicko]

Originally Posted by 1911su16b870

Jicko, I currently am shooting the 69-gr SMK HPBT and 75-gr TAP, but was looking up Sierra's bullet lengths for some stability calcs I was doing. I saw the info and figured I post it here as on topic. Sorry for the discrepancy? Maybe call Sierra tech services? allways wanted to use this smilie, I guess this is the place...

No no no..... thanks for the GOOD info..... I've already email'ed their tech, and we'll see what they say.... something doesn't add up here...

[Gunsrruss]

Originally Posted by XXX

Bolt2Bounce...Looks like you have had some success with WC 846. I also shoot some high power matches and wanted to know if you had any other recipes for 846 with possibly Sierra 69's or 80's. Thanks for you help.

I have loads for 69-80 Sierra. You might want to try 24.5gr WCC 846 with the 80's. With AOL 2.435. Now the 69gr Sierra I wanted a little more ummph so I used 24.5gr of WCC 844. Which is H335 equv. I quit buying the 69gr Sierra because they got so expensive. I went to the 75gr HPBT match Hornady. These I load with 24.7gr of WCC 846. I have 60lbs of 846 and 32lbs of 844 and make good use of it. I shoot 1X8 twist barrel. Now these loads work for me. I'm currently an NRA Master and got that way using these loads. I'm also starting to work with the 75-Amax to see if it helps me in the Off-hand position. I load these the same as the regular 75 but with an AOL of 2.390. Have a good day and be safe

[ocabj]

I found that link on the Sierra website interesting. I use 24.0gr of RL15 for the 77gr SMK/Nosler for my short line loads. I never really put much thought into it. Loaded some up. Shot a few groups. Did some chrono testing. Stuck with it. Shot no worse than MOA so I used it.

I pretty much use 24.0gr of RL15 for any 75-77gr bullet in LC brass. Everytime I do, the load shoots MOA at worst (out of a competition grade SR barrel).

[ar15barrels]

Originally Posted by Jicko

I understood that part, but BOTH quoted the SAME test spec

Were both loads tested in the exact SAME barrel?
If not, then don't worry about the actual velocity spec.
Velocities can run higher and lower in different barrels and pressures can still be fine.

[1911su16b870]

I called Sierra today and spoke with a ballistic tech, boy they are very personable and love shooting and talking about shooting with you!

A big +1 for Sierra.

[Jicko]

Thanks to SDJim, I've got some real Mk262Mod1 to test.

And duplication loads using 77gr HPBT SMK or NCC:

24.7gr RL15
CCI#41
LC case(06)

25.0gr RL15
CCI#BR4
LC case(06)

OAL: 2.246

MV: 2740 - 2800
Depends on the weather of the day. But it is within the 2770+-30fps.

[Sniped]

Great info. thanks to all that posted their results

BTT

[Darklyte27]

Hey Jicko, whats the update?

Id like to try to follow your steps in reloading.

Somewhat the same components,

I have some LC 07 brass wont matter much right?
Varget and 335 powder
# 41 CCI primers
Nosler 77 gr Custom Comp HPBT

after all that testing, what do you suggest trying out?

So what was the reason your rds were all over the place at the competition?

Thanks

[Jicko]

Let's try to add some more info for bullets other than the 77gr HPBT.

I think we should work on these first:
- 55gr FMJBT w/c or wo/c (M193)
- 62gr FMJBT w/steel-core (M855)
- 69gr HPBT
- 75gr HPBT

[Darklyte27]

I dont have any other bullets other than the 77 gr nosler one right now. I have some 69 gr ones coming in.

I also have some PPU 75 gr match stuff I bought that im going to try this weekend. Ill update on how that stuff shoots with pics.