Velocity Node: Do I have one?

[hardlyworking]

I am concerned I don't quite have this dialed in, looking for some assistance.

Loading up 223 in 2x fired PPU brass from my barrel (223 Wylde)
Hornady 35gr NTX copper for varmint/condor
Accurate 2200 powder is what I have on hand that is fast enough for this application
Magnetospeed Sporter, confirmed reading with a single XM193 round I had left over coming in at 3385 out of my 20" barrel

Loaded up three each of a 5-charge ladder starting at 27.0 in +0.3 increments single loading into magazine, taking my time, roughly 30-60 seconds between shots:
3832
3779 (bad reading?)
3855
3877
3933

Then I loaded up 5 in the magazine in increasing charge weight and only took enough time between shots to write down the velocity:
3796
3852
3854
3900
3952

And again for the 3rd replicate:
3814
3888
3903
3921
3974

When I plot these it looks like the middle charge is a "flater spot" but what has me a little sketchy is that at every charge weight as the barrel is warming up I'm adding apx 30 FPS so the lines don't lay on top of each other. I am having trouble with the concept of a "flat spot" on the velocity curve when the velocities go up with a warmer chamber. Though on all three curves the middle weight appears the flattest.

As a side note, the first 5 shot under 1" at 50 yards with a 4x scope even though the charge weight was increasing. But I wasn't really trying for groups I was only really interested in the velocity numbers.

Go back and re-test between 27.3 and 27.9?
Load up a raft of 27.6 and call it a great day?

[Whiterabbit]

Picture is worth a thousand words:



Answer, IMO: Velocity Node: No, you do not show one in this data set.

What do do about that answer? That's up to you. you can rock it, or retest, or change components, or whatever.

[ExtremeX]

I dont think you have enough data... in rounds and resolution to really be able to make any determination...

Instead of shooting a ladder each time, why not just look at the SD/ES for a given load, across the ladder itself?

[McGuiver]

Velocity Node: Do I have one?

I am concerned I don't quite have this dialed in, looking for some assistance.



Loading up 223 in 2x fired PPU brass from my barrel (223 Wylde)

Hornady 35gr NTX copper for varmint/condor

Accurate 2200 powder is what I have on hand that is fast enough for this application

Magnetospeed Sporter, confirmed reading with a single XM193 round I had left over coming in at 3385 out of my 20" barrel



Loaded up three each of a 5-charge ladder starting at 27.0 in +0.3 increments single loading into magazine, taking my time, roughly 30-60 seconds between shots:

3832

3779 (bad reading?)

3855

3877

3933



Then I loaded up 5 in the magazine in increasing charge weight and only took enough time between shots to write down the velocity:

3796

3852

3854

3900

3952



And again for the 3rd replicate:

3814

3888

3903

3921

3974



When I plot these it looks like the middle charge is a "flater spot" but what has me a little sketchy is that at every charge weight as the barrel is warming up I'm adding apx 30 FPS so the lines don't lay on top of each other. I am having trouble with the concept of a "flat spot" on the velocity curve when the velocities go up with a warmer chamber. Though on all three curves the middle weight appears the flattest.



As a side note, the first 5 shot under 1" at 50 yards with a 4x scope even though the charge weight was increasing. But I wasn't really trying for groups I was only really interested in the velocity numbers.



Go back and re-test between 27.3 and 27.9?

Load up a raft of 27.6 and call it a great day?

Sometimes the Bullet manufactures list powders that are not the best, but is what they had on hand for a loading section.

If you are going for long distance and a light bullet for small critters, you want speed and accuracy. I see that you are using a solid copper projectile. It may be light, but it is not as dense as it similar counterpart (lead with copper jacket). You bullet weight for weight will be slightly larger than a lead projectile. I have not seen many light solid copper projectiles fly well. Can you try a heavier projectile? What is the twist rate on the barrel?

Here is the load data I was looking at for Hornady. My guess off hand was to use TAC powder.

Accurate 2200 is not listed anywhere on the recommended load data...those are expensive bullets to shoot with a wild guess on powder.



Nosler has a similar bullet. I would use Nosler load data.





At those speeds, I might even think about CFE223 powder...Less copper fouling, but would need to work up a load.

IMR 8208 XBR would be a good choice too.


Sent from my iPad using Tapatalk

[hardlyworking]

Ok so if I don't have a node, do I need a broader range of charge weights? Like 26.0 to 28.0 and going in .2 steps?

Am I screwing up the analysis by doing multiples of the same charge weight? (or at least confusing myself?) This is my first time doing anything of the sort after watching the 6.5 Guys video with Scott Satterlee. I admit that I don't know as much as I probably should.

As for powder choice Accurate 2200 data was taken from the Western 2016 PDF off their website and while they didn't have the exact bullet I was using other 35gr projectiles as my base for 5.56 pressures here:
35 NOSLER BTLF 24.8 3,828 27.6 4,150 61,805 2.260
36 BARNES VG 25.3 3,718 28.1 4,086 62,030 2.190

You can see from my chronograph data that I'm putting up faster numbers than either the Hornady or Nosler info, and that's from a 20" barrel (1:8) rather than the 24" (1:12) standard. I can't say that its good or bad, but I feel like its at least a reasonable choice for these light-for-caliber bullets. It was not a wild guess. Western's own data for Ramshot TAC and X-Terminator stop at 49gr bullets on the low end and they make the stuff! I do have 8208XBR on hand, was under the impression that was for heavier bullets (69-77gr) ideally. Going to IMR their 8208 load tops out at 28.0 gr @ 3891 from a 24" barrel.

[LynnJr]

Use the 1% rule on your charge intervals. So a 20 grain charge would use 0.2 grain intervals and a 40 grain charge would use 0.4 grain intervals.
On the powder you want a powder that fills 85% of the case or more with your choice of bullet weight.
Check the online sources for factory recommendations.
Don't worry about finding a velocity node as chronograph error coupled with shooting style can greatly influence those results.
Accuracy is key.

[McGuiver]

Use the 1% rule on your charge intervals. So a 20 grain charge would use 0.2 grain intervals and a 40 grain charge would use 0.4 grain intervals.

On the powder you want a powder that fills 85% of the case or more with your choice of bullet weight.

Check the online sources for factory recommendations.

Don't worry about finding a velocity node as chronograph error coupled with shooting style can greatly influence those results.

Accuracy is key.

With a Magnetospeed I doubt there is much influenced error shot to shot. They seem pretty accurate. That will be my next purchase for a chrono.


Sent from my iPad using Tapatalk

[McGuiver]

Velocity Node: Do I have one?

Ok so if I don't have a node, do I need a broader range of charge weights? Like 26.0 to 28.0 and going in .2 steps?

Am I screwing up the analysis by doing multiples of the same charge weight? (or at least confusing myself?) This is my first time doing anything of the sort after watching the 6.5 Guys video with Scott Satterlee. I admit that I don't know as much as I probably should.

As for powder choice Accurate 2200 data was taken from the Western 2016 PDF off their website and while they didn't have the exact bullet I was using other 35gr projectiles as my base for 5.56 pressures here:
35 NOSLER BTLF 24.8 3,828 27.6 4,150 61,805 2.260
36 BARNES VG 25.3 3,718 28.1 4,086 62,030 2.190

You can see from my chronograph data that I'm putting up faster numbers than either the Hornady or Nosler info, and that's from a 20" barrel (1:8) rather than the 24" (1:12) standard. I can't say that its good or bad, but I feel like its at least a reasonable choice for these light-for-caliber bullets. It was not a wild guess. Western's own data for Ramshot TAC and X-Terminator stop at 49gr bullets on the low end and they make the stuff! I do have 8208XBR on hand, was under the impression that was for heavier bullets (69-77gr) ideally. Going to IMR their 8208 load tops out at 28.0 gr @ 3891 from a 24" barrel.

I'm sorry if you took it wrong about guessing on powder. I had an older version that did not list AA2200. I just downloaded the newest version. Do you want just flat out speed?

I know your using 5.56 pressure data, I usually use 223 and work up. Some places like Hodgdon don't differentiate.

Here is the newest PDF marked up.

TAC...



X-Terminator...



AA2200...



I have not loaded the solid copper Hornady small bullets. I have shot a lot of Z-Max 40gr and Nosler 40 gr ballistic tip bullets. I have loaded same brass head stamp, powder and primers. Load for load the Nosler's came up a little faster (could be error on my part). I know they are similar. I do shoot Z-Max because they are cheaper. It seems that sometimes the bullet data may be extrapolated too.

IMR 8208 XBR had the lowest SD numbers of all the powders I have shot so far with these 40gr bullets. I also load 8208 in my 80gr Nosler's. I want speed too, but over longer distance I want a lower SD number for my best shot grouping. If I want speed I go to a longer barrel.

How does the brass look after those fast shots? Flattened primers or loose primers? I had some fast rounds like that once and 5.56 brass was no good after 2 shots. Brass stretching (Near head case separation) and loose primer pockets. Wish I could crimp my primers in.


Sent from my iPad using Tapatalk

[Whiterabbit]

Ok so if I don't have a node, do I need a broader range of charge weights? Like 26.0 to 28.0 and going in .2 steps?

Am I screwing up the analysis by doing multiples of the same charge weight? (or at least confusing myself?) This is my first time doing anything of the sort after watching the 6.5 Guys video with Scott Satterlee. I admit that I don't know as much as I probably should.

Not gonna comment about your powder choice because I'm not qualified. I've used oddball powders for odd cartridges with great luck, and others I had to disqualify because I just could. not. make. it. work. Neither statement is useful for your needs with your cartridge with your powder choice.

To address the above quote:

You are NOT screwing up the analysis by running multiples. You make the data stronger. 3 round analysis IMO is perfect for velocity testing. Not so much data you blow the barrel out by the time you get the information you need, but enough data so that you can throw out a bad data or watch your ES open and close along with the real plot data, which is ave velocity to find the nodes.

But your first statement: what to do about no velocity node?

My answer:

Two things to factor into your decision. #1, why do we want flat spots in velocity? We do it so that variance in loading practices and variances in temperature, or whatever else affects burn, has a minimum effect on your velocity variance. Thus, if you are measuring powder to the kernel, and using a temp insensitive powder, and using a truck axel barrel, do you need to be at the flat spot, if you get better ES outside that node?

Remember, we are NOT finding barrel harmonic nodes or any of that jazz. Only velocity.

Second, do you even need to manage velocity like that? My 7mm mauser best load is likely outside a node, and has a huge ES besides. It doesn't affect me because I'm shooting man sized targets if I shoot past 200 yards, and velocity variance, who cares for target shooting at 100 yards?

NOW, my RPR target gun, absolutely I want to be in the node. So I make sure I develop there. But frankly I've never tracked the velocity node for any other gun. Because I don't need it.

-------

SO, I don't know what your application is, so I can't predict what need you have for velocity uniformity across cartridge loading variance. Even if you tell me your application I could probably only guess your velocity uniformity needs rather than actually know your needs. Probably most of calguns too.

In other words, you have to decide for yourself what to do, based on an understanding of what benefit being in the node gives you, and whether that is meaningful for you.

[hardlyworking]

Dang! Those are some outstanding thoughtful replies, thanks guys!

As far as application, I'm trying to develop loads for taking heads off of cottontails so I can preserve the meat. And I want speed so I don't have to worry at all about bullet drop inside of 200 yards.

I probably only need to touch them at these speeds so long as the bullet opens inside of half an inch.

But accuracy is important cause a bunny head is not a large target.

[Whiterabbit]

22 cal bullet going over 2000 fps, I'm pretty sure it doesn't need to open at all to kill bugs bunny.

[McGuiver]

Velocity Node: Do I have one?

Dang! Those are some outstanding thoughtful replies, thanks guys!



As far as application, I'm trying to develop loads for taking heads off of cottontails so I can preserve the meat. And I want speed so I don't have to worry at all about bullet drop inside of 200 yards.



I probably only need to touch them at these speeds so long as the bullet opens inside of half an inch.



But accuracy is important cause a bunny head is not a large target.

I thought you were shooting more than 200 yards. I could nail a bunny in the head with iron sights. Remember the lighter the bullet, the faster it starts, the faster it slows down.

Here are some bullet drop calculations for you...

40gr bullet - (0.2 BC) rifle zeroed for 100 yards.



80gr bullet - (0.415 BC) rifle zeroed for 100 yards.



Look at the drift between the 2 bullets at 200 yards. This is for a 10 MPH crosswind at 90 deg. Higher BC bullet cuts the wind better. Gravity always works the same (bullet drop should almost always be the same). The harder thing to predict is the wind.

At 600 yards the bullet drop is almost the same, but look at the wind drift for the 40gr vs the 80gr at 600 yards.

Depending on left or right handed twist in barrels at very long range can also effect bullet drop with wind vs wind direction. It can lift or force the bullet drop more. I find very long range shooting cool with the physics involved (including Coriolis effect).

https://thearmsguide.com/5329/external-ballistics-the-coriolis-effect-6-theory-section/

If you wanted to hit bunnies in the head inside of 200 yards a 17 HMR works well. I could nail a bunny out to 600 yards with a 223/5.56 round. Might not be in the head, but the 80gr bullet would not open up, just tumble thru.

Wind would be the head or body shot factor beyond 300 yards for me. I don't care about the speed, as long as they are accurate. Up to 200 yards, I could hit a bunny in the head with my 300 AAC setup running 125gr Speer TNT bullets. Those things shoot like laser beams (very accurate). They are only running about 2200 FPS...

In the end speed is nothing without accuracy. I would find the accuracy nodes (grouping) from a given barrel, then figure what I need the bullet to do. You may have 3 or more nodes that are 1 moa or less at 100 yards from a min to max charge weight. After that you could take the node you want and then play with bullet seating depth and maybe perfect your group even more.



Sent from my iPad using Tapatalk

[McGuiver]

Velocity Node: Do I have one?

Sorry, I forgot you were loading a 35gr bullet...NTX.



Here is the bullet drop calculation for your 35gr NTX with a .177 BC.



The BC for this 35 gr NTX is horrible @.177...

I would look at the Nosler Ballistic Tip Lead Free in 35 gr or 40 gr. 40 gr would be my choice.

http://www.shootersproshop.com/loading-reloading-bullets/nosler-22-40-grain-ballistic-tip-lead-free-bullets-blem-100ct.html

Just food for thought.






Sent from my iPad using Tapatalk

[Whiterabbit]

I got no skin in the game, but maybe cost or availability is a factor. I tried to make E-tips and custom competition bullets work in two rifles because the cost was half that of barnes and berger. Half. Today, I shoot barnes and berger. I couldn't make the noslers do what the barnes and bergers do. Wish I could. Barnes are expensive.

[ar15barrels]

I am concerned I don't quite have this dialed in, looking for some assistance.

Loading up 223 in 2x fired PPU brass from my barrel (223 Wylde)
Hornady 35gr NTX copper for varmint/condor
Accurate 2200 powder is what I have on hand that is fast enough for this application
Magnetospeed Sporter, confirmed reading with a single XM193 round I had left over coming in at 3385 out of my 20" barrel

Loaded up three each of a 5-charge ladder starting at 27.0 in +0.3 increments single loading into magazine, taking my time, roughly 30-60 seconds between shots:
3832
3779 (bad reading?)
3855
3877
3933

Then I loaded up 5 in the magazine in increasing charge weight and only took enough time between shots to write down the velocity:
3796
3852
3854
3900
3952

And again for the 3rd replicate:
3814
3888
3903
3921
3974

When I plot these it looks like the middle charge is a "flater spot" but what has me a little sketchy is that at every charge weight as the barrel is warming up I'm adding apx 30 FPS so the lines don't lay on top of each other. I am having trouble with the concept of a "flat spot" on the velocity curve when the velocities go up with a warmer chamber. Though on all three curves the middle weight appears the flattest.

As a side note, the first 5 shot under 1" at 50 yards with a 4x scope even though the charge weight was increasing. But I wasn't really trying for groups I was only really interested in the velocity numbers.

Go back and re-test between 27.3 and 27.9?
Load up a raft of 27.6 and call it a great day?

Do you even know how a proper ladder test is done?
Are you shooting a ladder test with the magnetospeed attached to your barrel?
That will only help you if you do ALL your shooting with the magnetospeed attached to your barrel as the megnetospeed dramatically effect the weight of the barrel...