Velocity difference between 26" barrel ar and 26" bolt action?

[jca57jd]

Hey gentleman,
I just built a ar10 in 243, 26" barrel, extended gas system, and adjustable gas block. I know that it's hard to be exact on how much loss in velocity I would experince do to being a gas gun but I was just wondering if there was a general rule to use on velocity loss for a ar? 10% loss in velocity when compared to a bolt action with the same barrel length?

Thanks!

 

[J E Custom]

Hey gentleman,
I just built a ar10 in 243, 26" barrel, extended gas system, and adjustable gas block. I know that it's hard to be exact on how much loss in velocity I would experince do to being a gas gun but I was just wondering if there was a general rule to use on velocity loss for a ar? 10% loss in velocity when compared to a bolt action with the same barrel length?

Thanks!

I don't think there is a percentage loss that could be counted on, because of the difference in Barrels, and loads. generally velocity will be less in a gas gun because some of the energy used
to operate the action is not used to propel the bullet like it is with a bolt action rifle.

The difference will be there although not much. The only way to know for sure is with the use of a chronograph.

I doubt it would be 10% though.

J E CUSTOM

 

[blksno]

10% would be CRAZY.

That's a 300 fps velocity loss for a 3000fps cartridge.

I wouldn't be surprised if it was 1-2%, but I'm betting it's a lot less than 5%.
Entirely possible that you can get right back to normal with some powder experimentation.

 

[jca57jd]

10% would be CRAZY.

That's a 300 fps velocity loss for a 3000fps cartridge.

I wouldn't be surprised if it was 1-2%, but I'm betting it's a lot less than 5%.
Entirely possible that you can get right back to normal with some powder experimentation.

I'm glad you responded oneilops! Is this James or Joe? If you choose not to answer I understand! I built this custom gun after watching the accuracy yall got out of your 243wsm! This gun has a 1-8" 26" Krieger custome barrel on it and I can't get any 105's to go over 2900 fps and according to quick load and multiple other sources I should be getting more with the charges I've been running. I'm shooting the Berger 105 hybrids. I've been doing the load development without my suppressor on because the gun was getting so dirty so fast. What would you do if you were in my situation? Many Thanks!!

 

[jca57jd]

Hear is a picture of her.

 

[blksno]

I'm glad you responded oneilops! Is this James or Joe? If you choose not to answer I understand! I built this custom gun after watching the accuracy yall got out of your 243wsm! This gun has a 1-8" 26" Krieger custome barrel on it and I can't get any 105's to go over 2900 fps and according to quick load and multiple other sources I should be getting more with the charges I've been running. I'm shooting the Berger 105 hybrids. I've been doing the load development without my suppressor on because the gun was getting so dirty so fast. What would you do if you were in my situation? Many Thanks!!

Yeah, this is Joe and that was my WSSM
Don't have it anymore, someone made an offer I couldn't refuse...and I'm already kicking myself for letting it go.
Missed a .25 WSSM Dtech upper on Gunbroker for a shade over $600. Kicking myself about that too haha.

I tested the Berger VLDs quite a bit before I gave up, but never had the chance to run the Hybrids. I gave up because mine was a 1:9 twist and the jump was too extreme to see any kind of decent accuracy with them...but it shot the 105 Amaxs with excellent results and more than excellent velocities.
If I remember correctly, I was getting around 3150 at mag length, and a bit faster after using the Pmags I modified, to run an OAL of 2.395.

What powder are you using. I know of one other fella that was running 105 Amax at a more conservative 2900 but I was doing quite a bit faster with RL17.
Unfortunately, I don't have very much of my old data left. It all went with the rifle to the new owner.

 

[jca57jd]

I've ran imr4350, h4831, h100v, and h1000, through it so far. I've got some 17, 22, varget, and trying to get some h4350. I think I might give up on the hybrids and move to the amax's.

 

[Greyfox]

I have seen little to no difference between my AR and bolt rifle in 223 using the same 55-69gr loads in each out of 24" varmint weight barrels.....under 20ft/sec. This was confirmed obseving the same POI at 500 yards with both.

 

[jca57jd]

Why do you think my 26" barrel is producing less velocity than what my reloading books are showing for a 24" barrel. Im even getting less muzzle velocity with 2 grains more powder than there max charge weights and velocity ratings? It confuses the crap out of me!

 

[Greyfox]

Why do you think my 26" barrel is producing less velocity than what my reloading books are showing for a 24" barrel. Im even getting less muzzle velocity with 2 grains more powder than there max charge weights and velocity ratings? It confuses the crap out of me!

I it possible your chronograph readings are off?

 

[budlight]

I've ran imr4350, h4831, h100v, and h1000, through it so far. I've got some 17, 22, varget, and trying to get some h4350. I think I might give up on the hybrids and move to the amax's.

Try Ramshot hunter and H superformance. I also have a 9 twist and found 100's to be the most accurate

The most accurate are not the max loads. I work up to an acceptable pressure level and then back off to find the best group

 

[reeloarknot]

I doubt there would be any significant difference, and it would be hard to prove the difference was not from a plethora of other variables in the make up of the two different barrels, not to mention variables in the rounds themselves. The bullet is only in the barrel for less than a milli seconds, and dwell time after passing the gas port is very short.

 

[blksno]

My best velocity was by FAR were with RL17. Accuracy was a toss up, between that and Varget.
My best load with the 105 Amax was in the 42.4 - 42.6gr range with 215 Mag primers seated to an OAL of 2.39" I believe.

DO NOT start that high, obviously. It will probably take a modified mag, and the longer OAL to run that much horse power (max is 41 for 100gr bullets), but those were running at about 3100 I believe.

 

[jca57jd]

Thanks cbass! I might try some r17. Did you use quickload for any starting points on this gun or some of your others?