Barrel length vs velocity

[lyle2231]

Asking for comments and opinions…I participate in NRA
High Power matches. I use an AR with an 18" barrel with adjustable gas block .223 Wylde chamber for across the course. Prone matches are with a bolt gun
in 6Br through a 26 inch barrel. I've documented my loads and my findings are that the 18" barrel has a shorter pressure curve duration evidenced by brass appearance compared to amount of powder in the case, at maximum or slightly exceeding. With the bolt gun I can't get close to maximum before I start getting pressure signs on the brass. Two different set ups yes but the question is pressure curve versus barrel length. What are your thoughts……

 

[Damage Inc.]

My thought is: how are you going to draw any reasonable conclusion when comparing brass from a gas gun, to brass from a bolt gun?

 

[lancetkenyon]

Gas guns and bolt guns are two totally different animals. Bolt guns handle pressures a LOT better.

 

[lyle2231]

My thought is: how are you going to draw any reasonable conclusion when comparing brass from a gas gun, to brass from a bolt gun?

Thanks for your reply. My curiosity is pressure curve compared to barrel length.

 

[lyle2231]

Gas guns and bolt guns are two totally different animals. Bolt guns handle pressures a LOT better.

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JoinedJan 26, 2014Messages533LocationHollywood

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My thought is: how are you going to draw any reasonable conclusion when comparing brass from a gas gun, to brass from a bolt gun?

Thanks for your reply. My curiosity is pressure curve compared to barrel length.

 

[MagnumManiac]

I doubt barrel length has anything to do with your observation of brass differences. I have pressure testing equipment and can tell you that a difference in pressure is VERY HARD to see on a brass case, and if you think it is the pressure curve effecting velocity, then you must have better knowledge than me. I cannot see a pressure curve on ANY brass I have ever fired.

Cheers.

 

[lyle2231]

I doubt barrel length has anything to do with your observation of brass differences. I have pressure testing equipment and can tell you that a difference in pressure is VERY HARD to see on a brass case, and if you think it is the pressure curve effecting velocity, then you must have better knowledge than me. I cannot see a pressure curve on ANY brass I have ever fired.

Cheers.

As an example; cratered primers, expansion at the web, ejector marks.

 

[lyle2231]

As an example; cratered primers, expansion at the web, ejector marks.

 

[Mike Matteson]

You have two different type of actions. What and where the pressure signs showing up in which rifle?

 

[lancetkenyon]

As an example; cratered primers, expansion at the web, ejector marks.

Way too many variables.
A sloppy firing pin hole will cause cratering, even at lower pressures.
A sloppy chamber can cause expansion issues.
Soft brass can show ejector marks, even at lower pressures. Nosler brass is notorious for this.

 

[Beluebow]

As an example; cratered primers, expansion at the web, ejector marks.

All three of those can be manipulated to show pressure.....cratered primer/oversize firing pin hole (esp with 6br brass), expansion at the web/fat chamber, ejector marks and pierced primers can be from excessive headspace. None of these are good indicators of a pressure curve difference on brass.

Was typing while Lance was posting....I agree with everything he said.

 

[MagnumManiac]

As an example; cratered primers, expansion at the web, ejector marks.

Please explain HOW this has ANYTHING to do with barrel LENGTH in your mind…because I CAN tell you what 'I' think is happening and it has nothing to do with barrel length…

Cheers.

 

[lyle2231]

Please explain HOW this has ANYTHING to do with barrel LENGTH in your mind…because I CAN tell you what 'I' think is happening and it has nothing to do with barrel length…

Cheers.

Okay then let's hear what you think

 

[MagnumManiac]

You are overloading your cases…period.

Cheers.