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Based on @OldVet's and my analysis of my posted data, I loaded up 25 rounds with 24.2 gr of A2520 and took off to the range to meet my PRS buddy.

At the end of the 25 shots, my jaw dropped when my Surface Go indicated an ES of 99! :aargh4: That's absolutely awful!

So this morning, I spent some time trying to make some sense of all this. It wasn't just one or two outliers (velocity outliers), but about 5, and that's just too many to ignore. So what the heck is going on???

I stuck a trend line on the velocity chart that looked more like a rugged mountain range profile than velocity numbers, but there it was! The velocity was steadily going up with each shot! Well, sort of with each shot.

I keep running overall stats and running stats on 5 shot groups also. The individual stats showed that the average velocity for the first 5 shots was 2686 fps and the average velocity on the last 5 shots was 2718 fps. That in and of itself would increase the offset by 32 fps. So if I adjust the 99 fps by 32 fps, I'd have a more accurate representation of the ES at 67 fps, now that's a little better!

But, there's more, and it just gets better!

So I thought, I know the velocity is steadily increasing very likely due to the ammo heating up from 75° to 91° and untelling how much the barrel was heating up, so I decided to treat the first three 5 shot groups as one single 15 shot group; the ES jumped to 71 fps! Three 5 shot groups with ESs of 46, 46, and 42 fps treated as a 15 shot group had a spread of 71 fps. Which would be the more accurate indicator?

Well, since this same charge, same primers, and same gun previously produced ESs just below 35 fps WITH 4 DIFFERENT BRANDS OF CASES, I might add, I think the ESs of the individual 5 shot groups are much more accurate than the 25 shot ES.

So, if you've been paying attention to my posts, you know that I believe it takes 15-20 "events" to accurately depict performance. This seems to fly in the face of that since the individual 5 shot groups seem to give more indicative results than the larger 25 shot group. But, that's not exactly right.

Remember I had 5, 5 shot groups that all favored 24.2 gr of powder. That's 25 shots, not 5. The thing here is the 25 shots were shot 5 shots at a time rather than the whole 25 in one session. Also, I now have 3 more 5 shot groups that indicate the ES is in the mid 40s; A little higher, but still well within reason. So that's a total of 40 shots in pretty close agreement. The average ES of the 40 shots would be right at 40 fps - a far cry from that 99 fps the 25 appeared to produce.

I am satisfied that the 99 fps spread was due to ammo and the barrel heating up. My buddy, felt of my barrel and suppressor and said it was smokin'. We didn't actually measure the barrel temp, but I can say this for sure, it sure wasn't that hot for the first 5 shots!

So guess what I'll be doing today? Well, you guessed it, shooting the very same load again, but slower and I'll be measuring the barrel temp.
 

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My head hurts...

There's a older fellow at my range who shoots the RPR, don't know what caliber though. He'll fire ONE shot, open the bolt, and insert a little tube from a battery-powered air pump in the chamber, and let it cool before he fires another shot. He might get off five rounds in a shooting session. Too extreme for my tastes, but you might consider it. Cools faster than sitting around waiting for convection to take place. It was a simple little rig, small air pump and tube.

Or you can just dunk your gun in a bucket of water between shots.:rolleyes:
 

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So these are different brands of brass, but are they all new brass? Have they been fired the same number of times?
 
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My head hurts...

There's a older fellow at my range who shoots the RPR, don't know what caliber though. He'll fire ONE shot, open the bolt, and insert a little tube from a battery-powered air pump in the chamber, and let it cool before he fires another shot. He might get off five rounds in a shooting session. Too extreme for my tastes, but you might consider it. Cools faster than sitting around waiting for convection to take place. It was a simple little rig, small air pump and tube.

Or you can just dunk your gun in a bucket of water between shots.:rolleyes:
I'm with you on that all the way! That's just a bit extreme for me. I can't make myself shoot that slow either.

My buddy has one of those, actually a couple of them. Frankly, I can't see that that little breeze of air would do a lot of cooling on the chunk of steel barrel on my AR, and much less on the big barrels he runs.

Now if you were to blow the air over a Peltor Effect device and get that 30° cooler than ambient air...I've been meaning to invent that as a matter of fact, but the drawback to it is the power drain on a battery to get the cooling, still maybe a USB power pack.
 

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So these are different brands of brass, but are they all new brass? Have they been fired the same number of times?
In the 25 round test that gave me the superficial 99 fps ES, that was all reloaded Lapua by about 4 times now.

In previous tests, I ran three sets of new Lapua, a set with Lapua reloads, a set with Hornady reloads 2x, and a set with Sig reloads, 2x. They all had a significant ES di,p less than 35 fps, at 24.2 grains.

I have another set loaded in Lapua cases, another 4x reloads, but this time I'm gonna monitor barrel and ammo temps.
 

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@Tangle , you have intrigued me enough to set up my chrono , I'm shooting 223 once fired brass ? cleaned and resized, no trimming, sorting, etc , the bullets are pulled 55gr , powder AA-2230 , cci primers , Hornady lnl press , lee dies

Savage mdl-12

Accuracy was not a concern as these bullets are ment for fun range time ..

10 shots through the chrono

1- 3274
2-3235
3-3227
4-3228
5-3223
6-3239
7-3247
8-3269
9-3250
10-3238
 

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@Tangle , you have intrigued me enough to set up my chrono , I'm shooting 223 once fired brass ? cleaned and resized, no trimming, sorting, etc , the bullets are pulled 55gr , powder AA-2230 , cci primers , Hornady lnl press , lee dies

Savage mdl-12

Accuracy was not a concern as these bullets are ment for fun range time ..

10 shots through the chrono

1- 3274
2-3235
3-3227
4-3228
5-3223
6-3239
7-3247
8-3269
9-3250
10-3238
I was going to ask if you had an AR to fire those loads through for comparison, but then I noticed you're in Noo Yawk.:rolleyes:

AVG - 3240, ES - 51. Not too bad.

What's the prize for the one who shoots an ES of Zero?

No, not a Christmas card.
 
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My head hurts...

There's a older fellow at my range who shoots the RPR, don't know what caliber though. He'll fire ONE shot, open the bolt, and insert a little tube from a battery-powered air pump in the chamber, and let it cool before he fires another shot. He might get off five rounds in a shooting session. Too extreme for my tastes, but you might consider it. Cools faster than sitting around waiting for convection to take place. It was a simple little rig, small air pump and tube.

Or you can just dunk your gun in a bucket of water between shots.:rolleyes:
I do recall a sniper in Afghanistan setting his ammo in the sun trying to warm them up to gain a little extra velocity before making a world record shot for the longest sniper kill, but I think for amp testing, that much effort to cool the barrel is either pointless, or he is among the top shooters in the world, and barrel temperature is the only remaining variable to his shots. If he goes through all that trouble to cool his barrel off, what is his plan for the next time he goes out when the weather is different, resulting in a different barrel temperature?


In the 25 round test that gave me the superficial 99 fps ES, that was all reloaded Lapua by about 4 times now.

In previous tests, I ran three sets of new Lapua, a set with Lapua reloads, a set with Hornady reloads 2x, and a set with Sig reloads, 2x. They all had a significant ES di,p less than 35 fps, at 24.2 grains.

I have another set loaded in Lapua cases, another 4x reloads, but this time I'm gonna monitor barrel and ammo temps.
How did the new lapuas compare to the others on that test?
 

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Discussion Starter #9
...How did the new lapuas compare to the others on that test?
Tough call really. Here's a plot of the cases. Several have a "strong point" in one area but don't do well in another. For example, the Sig 2x (green) had the lowest SD, but the worst accuracy.

 

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@Tangle , you have intrigued me enough to set up my chrono , I'm shooting 223 once fired brass ? cleaned and resized, no trimming, sorting, etc , the bullets are pulled 55gr , powder AA-2230 , cci primers , Hornady lnl press , lee dies

Savage mdl-12

Accuracy was not a concern as these bullets are ment for fun range time ..

10 shots through the chrono

1- 3274
2-3235
3-3227
4-3228
5-3223
6-3239
7-3247
8-3269
9-3250
10-3238
Thanks much for doing that! And thanks again for not just doing 5 shots :biggrin2:

I had mixed results today. I shot the same load again in four, 5 shot groups in an attempt to keep the barrel from heating up. And, based on my completely horizontal trend line on my velocity graph (not shown) - mission accomplished.

..............ES / SD
group 1: 58...26.0
group 2: 29...12.6
group 3: 22....9.3
group 4: 23....9.1

If you look at the four groups you can see why I say mixed results The first group was significantly different than the other 3 groups. I'm not sure what to make of this. The last three have incredible numbers and the first group is just OK.

The overall 20 shot stats are ES = 58 / SD = 14.9. The spread is not bad, but not good. The SD is pretty good. The low SD indicates most of the velocities were clustered close to the average. The higher ES, 58, indicates there was a few outliers.
 

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Thanks much for doing that! And thanks again for not just doing 5 shots :biggrin2:

I had mixed results today. I shot the same load again in four, 5 shot groups in an attempt to keep the barrel from heating up. And, based on my completely horizontal trend line on my velocity graph (not shown) - mission accomplished.

..............ES / SD
group 1: 58...26.0
group 2: 29...12.6
group 3: 22....9.3
group 4: 23....9.1

If you look at the four groups you can see why I say mixed results The first group was significantly different than the other 3 groups. I'm not sure what to make of this. The last three have incredible numbers and the first group is just OK.

The overall 20 shot stats are ES = 58 / SD = 14.9. The spread is not bad, but not good. The SD is pretty good. The low SD indicates most of the velocities were clustered close to the average. The higher ES, 58, indicates there was a few outliers.
The 10 shots I did for the chrono was one after the other , 3 rounds reload the mag 3 rounds etc the barrel was to hot to touch, this was after I sighted in a new scope ,

As @OldVet asked

I was going to ask if you had an AR to fire those loads through for comparison, but then I noticed you're in Noo Yawk.

AVG - 3240, ES - 51. Not too bad.

What's the prize for the one who shoots an ES of Zero?

No, not a Christmas card.

Do you think there would be a difference in ES from the AR to a bolt gun ?
 
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Will be interesting to see if at the end of all of this, whether or not you think Lapua cases are with the premium. You may find that they give a negligible advantage, which for semi auto may not matter much.


And you may save us all a lot of money in the process!
 

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The 10 shots I did for the chrono was one after the other , 3 rounds reload the mag 3 rounds etc the barrel was to hot to touch, this was after I sighted in a new scope ,

Do you think there would be a difference in ES from the AR to a bolt gun ?
If we're just talking accuracy then yes, I believe a bolt gun can be made to be more accurate than an AR semi can be made to be.

But, if we're talking numbers, i.e. ES and SD, then I'm not so sure. Yesterday my buddy shot 20, 223 precision handloads from his custom bolt gun. His numbers looked great for a while but then the ES eased up to 34 fps and by the time all 20 were shot his ES was around 54 fps as I recall.

Today, I got an ES of 58 fps from my AR and I'm not sure I'm tuned as well as I could be. So I'm not sure yet about ARs and bolt gun numbers. I'm gonna adjust my loads a bit and see if I can optimize some things and then my buddy and I will reshoot the bolt vs AR. Maybe that will shed some more light on the question.
 

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Will be interesting to see if at the end of all of this, whether or not you think Lapua cases are with the premium. You may find that they give a negligible advantage, which for semi auto may not matter much.


And you may save us all a lot of money in the process!
Well, I've heard good and bad about Lapua 223 brass. Of the top 100 Precision Rifle Shooter competitors, 46% use Lapua brass compared to Hornady in second place at 32%. Lapua is consider the gold standard.

However, that's for precision/long range calibers. I'm not so sure Lapua brass in 223 shines so brightly as their higher echelon lines. I've seen higher weight variations in Lapua brass than I would expect and I've read of others finding the same thing.

Here's the thing. the 223/556 is simply is not in the same league with the long range/precision calibers. The lowly 223/556 is rarely used in PRS etc for a number of reasons. One is it just doesn't have the ummph to reach out. Second the bullet weights and BCs are lower and don't carry as well and don't buck the wind as well. A 77 gr SMK fired from a 24" barrel will go transonic at about 950 yards. That means the trajectory is going to get squirrely as the bullet passes from supersonic to subsonic.

Because of this, I don't believe the lowly 223/556 components get as much love, attention, or QC from the manufacturers as the more popular PRS calibers.

I'm using Lapua 223 brass right now, but at this point in time, I can't say if the Lapua brass helps or not.
 

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Quite possibly.

@Tangle , you have intrigued me enough to set up my chrono , I'm shooting 223 once fired brass ? cleaned and resized, no trimming, sorting, etc , the bullets are pulled 55gr , powder AA-2230 , cci primers , Hornady lnl press , lee dies

Savage mdl-12

Accuracy was not a concern as these bullets are ment for fun range time ..

10 shots through the chrono

1- 3274
2-3235
3-3227
4-3228
5-3223
6-3239
7-3247
8-3269
9-3250
10-3238
Attached Thumbnails Attached Thumbnails
Reloading: When it ain't what it appears to be - something good!-img_1796.jpg


Ok I'm intrigued again and dug up my AR , it's nothing special, just a bunch of parts I aquired ,

1-2964
2-2942
3-2954
4-2978
5-2949
6-2956
7-2963
8-2962
9-2957
10-2942

And again this is after I sighted in the rifle , the 10 shot string was one after the other stopping to write the information and shoot again ,

This is the same ammunition , range fodder , plinking

I'm very surprised at the fps the savage 12 has a 26 inch barrel , the AR has a 16 inch barrel
I did choose the A-2230 powder for the shorter barrels , Thompson contenders ,
 

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36 fps ES for the AR versus 51 for the Savage. Interesting. I would have thought the opposite. Impressive ES for the AR. Both actually. The increase in the Savage velocities is notable, as would be expected.

My 6mm Mongoose barrel was 22", but I had the threaded muzzle cut off and a recessed target crown cut, so it measures about 21.25. My best ES so far--only tried out my chrono once--was with 27.8 grains of H335 under a 70-grain HPBT, ES of 27, SD 10 and 27.0 gains of same, ES 23/SD 10. All the loads with that powder and bullet had good results and worth tweaking. None of those loads had any exceptional efforts involved beyond typical reloading procedures.
 
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Thanks much for that @flh!

I just got back from the range and shot a 6x5 ladder (6 charges, 5 shots each charge). What a crazy session! I wanted to see how IMR 8208 XBR would do compared to A2520. This was the initial 5 shot sets to see if there would be any problems. If not, then I'll probably shoot the same 6x5 or a subset of it at least 2 more times to get the overall shot count up to 15 shots per charge.

..Vel....ES....SD...ES/SD ratio
2629...35...15.3......2.23
2675...34...13.4......2.54
2708...37...14.7......2.52
2740...23...10.2......2.26

As you can see these are outstanding numbers - something I've been looking for, for a loooooong time. But, then, the last two groups....:ticking:

..Vel....ES....SD
2768...67...26.9
2725...64...26.4

What on earth happened! Not only are the ESs/SDs large, the last group, 0.3 gr higher charge than the one before it, has an average velocity 43 fps slower! :blink:

And if that's not enough, one of the CCI 400 primers in this last group didn't fire.
 
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@Tangle , you have intrigued me enough to set up my chrono , I'm shooting 223 once fired brass ? cleaned and resized, no trimming, sorting, etc , the bullets are pulled 55gr , powder AA-2230 , cci primers , Hornady lnl press , lee dies

Savage mdl-12

Accuracy was not a concern as these bullets are ment for fun range time ..

10 shots through the chrono

1- 3274
2-3235
3-3227
4-3228
5-3223
6-3239
7-3247
8-3269
9-3250
10-3238
Attached Thumbnails Attached Thumbnails
Reloading: When it ain't what it appears to be - something good!-img_1796.jpg


Ok I'm intrigued again and dug up my AR , it's nothing special, just a bunch of parts I aquired ,

1-2964
2-2942
3-2954
4-2978
5-2949
6-2956
7-2963
8-2962
9-2957
10-2942

And again this is after I sighted in the rifle , the 10 shot string was one after the other stopping to write the information and shoot again ,

This is the same ammunition , range fodder , plinking

I'm very surprised at the fps the savage 12 has a 26 inch barrel , the AR has a 16 inch barrel
I did choose the A-2230 powder for the shorter barrels , Thompson contenders ,


To add a lil more information , I took 10 of the pulled bullets and weighed them 55.3 to 54.5 gr

To compare , Hornady match , 52.1 to 52.0 gr

Sierra match king 69.1 to 69.0 gr
 
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As you can see these are outstanding numbers - something I've been looking for, for a loooooong time. But, then, the last two groups....

..Vel....ES....SD
2768...67...26.9
2725...64...26.4

What on earth happened! Not only are the ESs/SDs large, the last group, 0.3 gr higher charge than the one before it, has an average velocity 43 fps slower!


^^^^^^^A hot barrel induces inconsistency?
 
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