Stuck case in chamber

[jdyoung]

Let me throw another one at the hive. I made a mistake referring to my measurements earlier. My average Chamber length was 2.890 (case length to ogive). I loaded all my rounds to 2.850 (ogive). That would give me .040 off lands...not the .005 like I had thought. Guess that's why you keep notes.
I've added a photo with the primers and charges. You can see there is some flattening, I just don't really believe that it is significant enough that I should be concerned with the pressure at 70grains. Again this yielded the best group at about .5moa. Could slight flattening be an indication of excessive head space? It's still closer to the lands than factory ammo, but with higher charge, I'm wondering if this could be a culprit to the stuck case at 70.5g, and if my 70g load, which shot great and had no extraction issues, should even be a concern at all?

Would .040" off the lands, and the charge at 70,5g be a compressed load ?

 

[BearDog]

Would .040" off the lands, and the charge at 70,5g be a compressed load ?

That's a good point....maybe?? A 70.5g charge would be about 92% volume. I didn't experience any notable differences in seating like crunch, or difficulty getting consistent depths. Powder still shakes in the loaded rounds. I've never worked with compressed loads so I don't know the key indicators.

 

[jdyoung]

Ran that load through QuickLOAD.

Used Specs I got from OP's first post:----- .300 WM , 180 g Nosler AB, IMR4831 71.0 g , used the programs SAAMI cartridge specs 'cause I didn't know overall length. (SAAMI cartridge overall length 3.340")

Results came up all in RED, Load exceeds Maximum Average Pressure! Do NOT USE THIS LOAD! Warning 0.7% compressed charge and 73,673psi .

It's possible that if the seating depth measurement to ogive of .040" is deeper than SAAMI specs, the compression will go up and of course so will the pressure.

 

[jdyoung]

That's a good point....maybe?? A 70.5g charge would be about 92% volume. I didn't experience any notable differences in seating like crunch, or difficulty getting consistent depths. Powder still shakes in the loaded rounds. I've never worked with compressed loads so I don't know the key indicators.

71 g of IMR4831 - Volume/Filling Load Ratio is 100.8%.
The good thing is you burnt 100 % of the charge.

 

[BearDog]

71 g of IMR4831 - Volume/Filling Load Ratio is 100.8%.
The good thing is you burnt 100 % of the charge.

That's cool software. I didn't know that existed. My COAL is at 3.487 (2.850 to the ogive).

 

[eschafer]

the brass.... how many times fired? was it only fired in the new chamber/barrel?

 

[BearDog]

the brass.... how many times fired? was it only fired in the new chamber/barrel?

Once fired out of the previous chamber. Full length sized. Case length all at 2.615 (2.620 max case length spec).

 

[eschafer]

use virgin brass to new chamber/barrel only... many nightmares are often the result of brass fired in another chamber....

 

[jdyoung]

That's cool software. I didn't know that existed. My COAL is at 3.487 (2.850 to the ogive).

Yeah it works for me !!! With that COAL , you are below the danger zone, but still 85% -100% of SAAMI max pressure.
What primer are you using ? That could be a factor which would increase pressure over MAX.

 

[Tiny Tim]

Nosler Load Data shows 73.0 IMR 4381 as max with a COAL of 3.330 and 94% load density running 3160 FPS in a 24" barrel. You are below that and longer in COAL. Doesn't mean its not over max in your rifle. What velocities were you getting? Many pressure signs to look for, Not all show up simultaneously. New chamber certainly needs new work-up. Back off and work back up slowly, checking everything in every step along the way. We read about the awesome speeds others are getting and we are often tempted to chase speed rather than accuracy.

 

[7070yshot]

I recently had a proof barrel put on my .300WM Sendero. I'm working on developing a load, and have yielded good results from 70gr of IMR4831, with a Nosler AB 180gr. In fact that is the same recipe for the weapon prior to adding the new barrel.

Here is my "hmmmm" moment. I had no indication of over pressure from that build. No bulging, cracking, sticking, and primers looked good. HOWEVER...when I went up to 70.5 during my test, my case was stuck and I had to try quite a few times to get the bolt to latch on and extract. This was the same for all of the rounds loaded at 70.5. At 71 gr I had to use a rod to get it out. I tested it again with a factory load and had no issues with extraction. All my cases are full length sized and under max case length. Bullet is seated .005 off lans. The max load for that powder is 73.

Why this worries me is if I'm getting stuck with a .5 gr increase going 70 to 70.5, is 70gr too risky to use when hunting? I was lucky enough to draw a moose tag for my home state and can't have a stuck case screwing that up. I don't know if temp changes will impact the material enough to where even the expansion for my 70gr charge will cause the case to stick. Could it be something else??

What's was the temp? And other environmental readings.
seems a little close for the Nosler but it is a long bullet.
What is your neck tension?
What is your primer depth?

 

[zb338]

Very good and very informative Doubleezranch. I have been shooting for a long, long time and did
not know about that technique. It's stuff like that that makes this Blog priceless.

Zeke

 

[Rich Coyle]

My rifle had stuck cases on less than full throttle loads. Discovered the extractor was the problem. Replaced it and problem solved.

 

[gunnerrun]

I recently had a proof barrel put on my .300WM Sendero. I'm working on developing a load, and have yielded good results from 70gr of IMR4831, with a Nosler AB 180gr. In fact that is the same recipe for the weapon prior to adding the new barrel.

Here is my "hmmmm" moment. I had no indication of over pressure from that build. No bulging, cracking, sticking, and primers looked good. HOWEVER...when I went up to 70.5 during my test, my case was stuck and I had to try quite a few times to get the bolt to latch on and extract. This was the same for all of the rounds loaded at 70.5. At 71 gr I had to use a rod to get it out. I tested it again with a factory load and had no issues with extraction. All my cases are full length sized and under max case length. Bullet is seated .005 off lans. The max load for that powder is 73.

Why this worries me is if I'm getting stuck with a .5 gr increase going 70 to 70.5, is 70gr too risky to use when hunting? I was lucky enough to draw a moose tag for my home state and can't have a stuck case screwing that up. I don't know if temp changes will impact the material enough to where even the expansion for my 70gr charge will cause the case to stick. Could it be something else??

Sounds like you examined the case well enough to have noticed any reamer chatter marks. If not you should consider that as a potential problem.