Over Pressure w/o Increased Velocity

[mikemo4032]

I had my 6GT dialed in with Berger 109's and 35.2g RL-16 at 80 degrees and thought I would do a tall target test for something to do. It was near 90 degrees and right away I noticed a stiff bolt. I shot as few more and pierced a primer so I shot 2 more through the mag speed and quit for the day. Before my last match, my average V was 2950. Today it was 2940. How can I have a clear overpressure condition without a V increase?

 

[26Reload]

Good question...bad situation...
Dirty barrel?.....carbon ring?....

 

[mikemo4032]

Not likely either. I looked for the ring and after a 100 round match last weekend cleaned thoroughly.

 

[mikemo4032]

I should add that my load of 35.5g RL-16 was about 1gr. below max load. I realize that RL-16 is not the best with respect to temp stability and in all likelyhood the hotter temps pushed it over the limit. I just thought it should be accompanied by a velocity increase.

 

[milo-2]

I should add that my load of 35.5g RL-16 was about 1gr. below max load. I realize that RL-16 is not the best with respect to temp stability and in all likelyhood the hotter temps pushed it over the limit. I just thought it should be accompanied by a velocity increase.

I believe RL 16 is the most stable powder on the market, but we can disagree. Run your scope down your barrel again, usually a increase in pressure with a velocity loss means the muzzle end of your barrel is getting slugged up. It is drag.

 

[mikemo4032]

I believe RL 16 is the most stable powder on the market, but we can disagree. Run your scope down your barrel again, usually a increase in pressure with a velocity loss means the muzzle end of your barrel is getting slugged up. It is drag.

Ok, thanks. I'll clean again and take a look.

 

[308win]

You said 35.2gr in your first post then came back with 35.5 in your next post. Maybe there's your problem?

 

[mikemo4032]

You said 35.2gr in your first post then came back with 35.5 in your next post. Maybe there's your problem?

Thanks, but no, my problem is age. I am at 35.2g and 68years.

 

[wvelk huntr]

A wet chamber could give you pressure signs and without an increase velocity. Might be worth checking that the chamber is dry

 

[MagnumManiac]

Had similar issue with my 6.5x47, left oil in the chamber and forgot to wipe it out prior to shooting. First 4 rounds had stiff bolt lift and ejector marks. Had me perplexed until I saw the oily cases.
I now always swab out my chambers/bores before shooting.

Cheers.

 

[Beluebow]

Got any leftover ammo that you can pull the bullet and check the charge?

 

[wonderman4]

An increase in pressure does not always mean an increase in velocity.

 

[deweyduck]

68 years plus 14 plus bad eyes plus handshakes = more problems than I deserve. But never give up trying for that elusive bug hole accuracy. Carbon rings are another problem that must be dealt with more often than we expect.

 

[26Reload]

Curious if a lot of guys that are using RL powders are suffering from premature carbon ring buildup.....
In my 65284s I see it within 30 rounds of RL23 and RL26...