Need help with 450 Bushmaster loads.

[jagermaster]

I think I answered my own question. I shot some 400 gr cast bullets today using 4198 and 5744 powder. I started at 19 grs with the 4198 and 20 grs with the 5744. I increased the powder charge 1 gr for 10 rounds each. Action stayed open on all of the powder charges. Velocity was around 900 fps on the low end and at the high charges the velocity around 1400 fps. Lots of unburned powder -- especially with 5744.

I noticed on the upper end of the charges, with both powders, that the cases had shave marks on the base (bottom) from the extractor groove in the bolt face. Indicating to me that two things were happening -- 1. Chamber pressure was now high enough to seal the case against the chamber walls -- 2. Chamber pressure was still high when the bolt was trying to open, most likely because the bullet had not exited the barrel yet.

Primers showed no pressure signs and actually looked very mild. I had used CCI 450 Mags (Small Rifle Magnum).

Velocity maybe needs to be at least 1700 fps (lowest velocity in Hornadys load data) to provide proper timing for bullet exit prior to chamber opening.

Any comments??

Hornady has load data for 400gr cast?
Please share.

[jagermaster]

QUOTE=Slash2]Hey, Jagermaster, did you ever get a chance to check the accuracy on some hotter loads than 37gs H110 for the Barnes 275's?



Yes I did.
I have not gotten around to posting the info yet because if im at the computer I do not have the info.
I know that sounds like an excuse, because it is.
I think that the charge was 28gr of h110 but I must
double check that.

Ten shots 100yds crony 10ft from mussel
Average velocity 2020fps
High 2053fps
Low 1975fps
Extreme spread 78fps
If I only count 9shots it was a 2in group
If I include all 10 rounds it is a 2.5in group

I also loaded a 38.5gr and a 39gr.

38.5gr 2058fps
39gr 2085fps

At 39gr it is near 100% case capacity. I could barely hear powder rolling around when I shook the case.

I belive I have hit a wall with the h110 and the barns bullets. From what I have read h110 has very little air space between the grains and it needs more air to
ignite fully. But what do I know ha ha

I purchased some lilGun this week and will start testing the barns with that powder.

As a side note have you seen the new ftx reloading data on hornadys website?

[GunNut]

As of 04.09.09, 6:30pm Ableammo.com has 450 bushmaster ammo.

[Siringo]

Hornady has load data for 400gr cast?
Please share.

Hornady doesn't have it -- it was what I loaded up. I used 27 grs of Lil'Gun with a 400 gr. 45-70 bullet sized to .452. Velocities ran around 1550 fps. I feel that is too slow for proper unlocking of the action.

On another note -- my load that I use for the 275 gr. Barnes is 35 grs of Lil'Gun. Velocity was about 2050 fps. Accuracy was 1 1/2 inches.

[Siringo]

QUOTE=Slash2]Hey, Jagermaster, did you ever get a chance to check the accuracy on some hotter loads than 37gs H110 for the Barnes 275's?



Yes I did.
I have not gotten around to posting the info yet because if im at the computer I do not have the info.
I know that sounds like an excuse, because it is.
I think that the charge was 28gr of h110 but I must
double check that.

Ten shots 100yds crony 10ft from mussel
Average velocity 2020fps
High 2053fps
Low 1975fps
Extreme spread 78fps
If I only count 9shots it was a 2in group
If I include all 10 rounds it is a 2.5in group

I also loaded a 38.5gr and a 39gr.

38.5gr 2058fps
39gr 2085fps

At 39gr it is near 100% case capacity. I could barely hear powder rolling around when I shook the case.

I belive I have hit a wall with the h110 and the barns bullets. From what I have read h110 has very little air space between the grains and it needs more air to
ignite fully. But what do I know ha ha

I purchased some lilGun this week and will start testing the barns with that powder.

As a side note have you seen the new ftx reloading data on hornadys website?

Just looked at their website. In the beginning they pushed H110 as the powder of choice for the 450. But now according to their load data on line -- Lil'Gun is the go to powder. They must read the posts on this site!!!! I have some of the new FXT's and will be doing some testing this weekend.

[NordicRX8]

Thanks guys!

Hello all,

I recently (about a month ago), purchased a Bushmaster 450, 20" rifle. Finding ammo has been a bear and decided to look for some recipes and found this wonderful forum. By far the best data has been posted here on this new caliber.

I'd like to thank all the forward thinking, brave souls who have the guts to work up loads the rest of us can use in our reloads. The time and effort (as well as expense), you have spent developing loads for this new caliber is very much appreciated.

I've only been able to purchase 120 rounds of factory ammo and have only shot 40 rounds of said ammo, but am ordering the Hornady dies and should have them here soon. I have plenty of Hornady 240g XTP/Mag bullets on hand and plan on using these to start my reloads with. The THUMPER is a lot more fun to shoot than the 223s!

Keep up the good work! The 450 bushmaster fans (and detractors) are watching (and learning)!

Regards,
Nordic

[Siringo]

Hello all,

I recently (about a month ago), purchased a Bushmaster 450, 20" rifle. Finding ammo has been a bear and decided to look for some recipes and found this wonderful forum. By far the best data has been posted here on this new caliber.

I'd like to thank all the forward thinking, brave souls who have the guts to work up loads the rest of us can use in our reloads. The time and effort (as well as expense), you have spent developing loads for this new caliber is very much appreciated.

I've only been able to purchase 120 rounds of factory ammo and have only shot 40 rounds of said ammo, but am ordering the Hornady dies and should have them here soon. I have plenty of Hornady 240g XTP/Mag bullets on hand and plan on using these to start my reloads with. The THUMPER is a lot more fun to shoot than the 223s!

Keep up the good work! The 450 bushmaster fans (and detractors) are watching (and learning)!

Regards,
Nordic

Welcome aboard!

[Slash2]

The 450 bushmaster fans (and detractors) are watching (and learning)

Detractors? What's not to love?

So what are some of the other forums that are discussing the 450B? Does anyone have a list?

[NordicRX8]

Detractors? What's not to love?

The fact that they don't own one yet?

So what are some of the other forums that are discussing the 450B? Does anyone have a list?

I did a google and came up with a few places (forums) that had some detractors and a few fans.

AR15.com
THR

if I recall correctly... this forum and thread was pretty far down the list and pages for 450 Bushmaster. Most of the hate came from mostly fans of "other big bore" AR15 rifles... afterall, who wants to hear that the choice THEY made was a wrong one?

As with other items people purchase... no-one wants to be told that whatever they chose was a bad decision... be it guns, cars, laptops, watches or sunglasses. eg: "RayBans suck! Maui Jim Rocks!" or "I'd never own a Glock, but my XD is the ultimate carry gun."

Personally, I wanted a bigbore AR platform that used a straight walled cartridge, and was backed by a major arms maker and ammo maker. Only one platform met those needs.

[Slash2]

Personally, I wanted a bigbore AR platform that used a straight walled cartridge, and was backed by a major arms maker and ammo maker. Only one platform met those needs.

That was my reasoning as well NordicRX8, welcome to the group!

[Siringo]

Back to 400's

I shot 5 rounds today over the chrony. I used the 400 grain Speer, sized from .458 to .452. Used Lil'Gun and WSR Primers.

Charges and velocities are as follows:

1 -- 27 grs, 1576 fps
2 -- 28 grs, 1614 fps
3 -- 29 grs, 1689 fps
4 -- 30 grs, 1736 fps
5 -- 31 grs, 1768 fps

Shots 3,4 and 5 all grouped in to .75". Shot #1 was 3 inches below cluster and Shot #2 was 2 inches below cluster. Sweet spot must be 30 grains.

Charges #1 and #2 show nil primer flattening. Charges #3 thru #5 showed progressive flattening. ALL CASES SHOWED WIPE MARKS FROM THE EXTRACTOR AREA ON THE BASE AND SHOT #5 SHOWED EJECTOR SWIPE.

I would consider this data the upper extreme and would be very, very cautious about its us.

[Siringo]

250 FXT's

Shot some of these today also. I had two previous loads that I had worked up using Muzzle Loader bullets.

I used Lil'Gun and WSR primers. Two charges were used -- 35.1 grs and 37.0 grs. With each I fired 4 - 2 shot groups (something new to try)

With 35.1 grs,, Av. Velocity -- 2127 fps, ES -- 112 fps, SD -- 47 fps.
Group 1 -- .25 inches
Group 2 -- .5 inches
Group 3 -- 1.4 inches
Group 4 -- 1.0 inches.

With 37.0 grs, Avg. Velocity -- 2218 fps, ES 67 fps, Sd -- 23 fps
Group 1 -- .25 inches
Group 2 -- .50 inches
Group 3 -- 1.1 inches
Group 4 -- .90 inhces

I used a target that had muliple squares and the small group sizes on the first two groups where at larger squares that I could see better. I have a 4 power scope. Also, the barrel length is 16 inches.

In my rifle, the 37.0 gr load shoots about as well as the factory, but 160 fps faster.

[BD1]

Hi All,

I'm new to Calguns, and the .450 B, but not so new to reloading. My 16" .450 upper is at the smiths getting a brake to make it NYS legal, and I'm waiting on a lower. In the meantime I've been reading this thread and fiddling around with the interior ballistics a bit.

My interest in the .450 B is primarily oriented towards cast boolits. And I've mostly looked at them.

The following are strictly my theoretical opinions and they have not been tested in the real world at this point.

I've reached a couple of preliminary conclusions: Quickload is telling me that Lil Gun is definately "The powder" for this cartridge, with H110 and N110 tied for second place. It looks like this cartridge will run on on lot of stuff like 4227, 1680, Enforcer, 5744, and #9, but Lil Gun has the advantage of higher velocities at lower pressures, and 100% combustion before the bullet exits the barrel, even in the 16" barrels, while staying under 40,000 psi. IMHO combustion over 95% is a big plus in a gas gun.

My second conclusion is that crimp is going to play a significant role. And it looks like achieving a solid crimp may be a challenge. As a straight wall cartridge of limited case capacity and a short throat, the bullet start pressure can be significant. Having the bullet jump forward into the lands as a result of the bolt momentum can add 6,000 - 8,000 psi to your peak pressure, (probably more with a solid copper bullet), and shift that peak earlier in the bullets travel. As the short throat limits the amount of extra case volume gained when the bullet moves forward, there is not as much "offset" as there might be using a bottle necked case in a similar situation, so peak pressure could go significantly higher with little difference in velocity, making shot to shot variation an issue.

I'm curious how much bullet jump you guys have experienced so far?
Earlier in the thread I read of a modified Lee FCD being used to place a solid crimp farther back on the case. How has that worked out?

I've got a couple of other questions as well. How high above the bore are you mounting your optics? How is brass life, particularly for you guys who are pushing the envelope a little?

And how are you dealing with recoil? I'll need to add a little length of pull to this rifle. I shoot my HP AR with my nose right on the charging handle. I suspect that's not gonna be a smart plan with the .450B. Any good experiences with a particular recoil pad?

I appreciate any help you guys with some experience can give me at this point.

BD

[MudBug]

This thread is definately the best resource for the 450b on the net. THe only problem is that actually getting the info out of this thread can be a pain in the butt since the only way to do it is by reading the whole thing.

So I'm wondering... I have some webspace that I have not been using and could set up a dedicated 450B forum, but it wouldn't be any use unless those of you here that have done so much wanted to drag all your testing, tips, and data over to the site, would you guys be interested in this?

I don't anticipate the forum being a high traffic madhouse just because the 450b has a limited user base, so it wouldn't be hard to run.


Whatchoo guys think?

[volt]

New 450 bushmaster fourm

Sounds Great but I'am new and have little to add.

I just got my second AR it's a 16in. 450 bushmaster on a Rock river lower

2 stage trigger.

This thread is very good the best I have found. and your right it's hard to

find the right information with out reading it over and over!

I want to work on 200gr JFP .451 loads to keep cost down.

I will add results as experience increases.