Hard bolt close help

[alphapygmy]

Hi guys, I need some help diagnosing a bolt that's hard to close. I've exhausted my knowledge and can't figure it out. It's a Savage PTA chambered in 6-BRDX, .272 neck. I think it's come on gradually, nothing went pop or boom then the hard closing. First I suspected not enough shoulder bump. I normally push the shoulder back about .0015. I eventually bumped a test case back .004 and still no better. Then I checked the base size. The fired brass is coming out .4715 and after sizing it comes out as .4705, should be good to go but still hard to close. Tried trimming the case length down even though it's .015" short according to reamer drawing-still hard closing. Hard carbon in the neck? Tried gently cleaning things up with the reamer hoping it would clean up the neck area if there was carbon. No good, still hard to close. I Sharpied a test case from top to bottom that measured good every way I could figure and it shows no rubbing or tightness anywhere. When just closing the bolt on an empty chamber it's smooth as can be. I figure the brass is getting work hardened but it measures good and the Sharpie test didn't show any tightness, primer pockets loosening a bit but still good after 7 firings. I'm stumped....

 

[Hal]

Have you tried a piece of new brass.

Hal

 

[cdparker]

Look at the neck-shoulder junction. If your die does not go to the very bottom of the neck, that may be one place to look.
Just a thought.

 

[savagedasher]

Have you tried a piece of new brass.

Hal

Put a piece of masking tape on the case bolt head trim it to fit .
If the bolt won't close you have head space to tight . Larry

 

[LRPV]

You may have something binding up your ejector. Another thought would be to take your bolt apart to make sure everything is happy in there. I once broke a little metal piece that keeps the firing pin spring where it belongs. It didn't make things any smoother either.

 

[alphapygmy]

-Definitely not the ejector-I don't run one.
-I've been doing all this with the bolt apart so it's nothing in the bolt.
-I used a Whidden case gauge to measure fired case headspace and after sized headspace. I'm bumping back between .0015-.002" so I'm pretty sure it's not tight headpsace.
-I thinkcdparker might have it. I used a .284 comparator to measure the shoulder-neck junction and a fresh fire formed case was .002 shorter here than my 7 times fired cases. Since there is a small chamfer in the sizing bushing I'm guessing it's not sizing there and crush fitting when I close the bolt. I pushed the bolt in hard a couple times and there's a very faint rub mark on the shoulder neck junction where I Sharpied the case.

So if that's the problem is there a fix that doesn't take a bunch of money for a custom non-bushing die? Thanks all

 

[DOGCAPPER]

You may have some unburned powder between the bolt and the barrel.

 

[swc123]

Do you anneal your cases?
If not, something you might try.

 

[jr600yd]

I had the exact same problem after fireforming some 6XC brass. Drove me nuts! Like you, I found the neck/shoulder junction a little larger than the neck. I changed from a bushing die to one with an expander ball. Didn't help. What it turned out to be was the dreaded "Donut". The bushing didn't size all the way to the neck shoulder junction and the expander ball forced it to the outside of the neck.

Solution:
I neck turned the cases just to clean them up and cut into the shoulder about 1/8". Problem solved.

 

[hogpatrol]

Check the screws on your front scope bases.

 

[alphapygmy]

cdparker had it right. I've confirmed the cases are not getting sized in the neck shoulder junction due to the chamfer in the sizing bushing. On my test case I completely cut off the neck and just into the shoulder and the bolt closed perfectly. Now I need to figure out how to size that part of the case. I really don't want to spend the money on a custom non-bushing FL die. Maybe a Forster Dasher die neck honed where I need it and trimmed short like you do for a 6 BR-AI. I just find their dies very tight in the base usually.

Any other ideas?

 

[savagedasher]

If you have hard bolt closing . Wouldn't that tell something is not fiting . If the bolt closes ok without a case . Then I would assume it was the case that was the problem . Why would you not make the case longer to check . A piece of tape on the head of the case will tell the case is too long . Larry

 

[alphapygmy]

If you have hard bolt closing . Wouldn't that tell something is not fiting . If the bolt closes ok without a case . Then I would assume it was the case that was the problem . Why would you not make the case longer to check . A piece of tape on the head of the case will tell the case is too long . Larry

I assumed the brass wasn't fitting but didn't know where else to check besides headspace, case length, and base size. It was the case not fitting the chamber due to insufficient sizing at the neck-shoulder junction as cdparker suggested. As mentioned before, I measured the headspace of fired and resized brass and that was not the problem. Also, I'm under the impression tape on a case tells if the chamber is too long or the brass too short. If I'm already running brass .0015 under chamber size adding .005 tape will not let the bolt close at all so I'm not sure what that tells me.

Now that the problem is identified I need a solution. This week is my clubs last shoot for points so I'll wing it to finish the season. After that I can give it a break and think on my options.

 

[savagedasher]

I assumed the brass wasn't fitting but didn't know where else to check besides headspace, case length, and base size. It was the case not fitting the chamber due to insufficient sizing at the neck-shoulder junction as cdparker suggested. As mentioned before, I measured the headspace of fired and resized brass and that was not the problem. Also, I'm under the impression tape on a case tells if the chamber is too long or the brass too short. If I'm already running brass .0015 under chamber size adding .005 tape will not let the bolt close at all so I'm not sure what that tells me.

Now that the problem is identified I need a solution. This week is my clubs last shoot for points so I'll wing it to finish the season. After that I can give it a break and think on my options.

That would tell your measurements are off . The brass is the same a a gauge . Shorten the neck . If it still doesn't move the shoulder . Most of the brass gets over size and you have trouble with extracting Larry