Bolt Wouldn't Open!

D

DocGlenn

Sergeant
Full Member
Minuteman
Jan 12, 2006
142
0
North Georgia
#1
Need some help here. Was shooting my 300 WSM yesterday, shot 12 rounds of 64.5 gr of 4350 (I think, don't have data here) w/ a 165 gr SGK at 2950 fps).

Out of the 12 rounds, I couldn't open the bolt after firing twice. The bolt handle lifted w/o any problems (may have been a little tight, but not enough to really notice), but I couldn't open the bolt after lifting the handle. Actually had to tap it open with a rubber mallet. All rounds were loaded at the same time with the same componets out of the same containers.
I'm assuming these 2 rounds were "hot"? I just really have no idea how the other 10 rounds ejected normally and 2 of them got "hammer stuck". WTF did I do wrong? I'd really appreciate any help I can geton this one. Thanks!
 
#2
Re: Bolt Wouldn't Open!

When you have issues like that, seperate that brass so you can inspect it for the usual high pressure signs, sticky bolt, flat primers, ejector swipe marks.
If you have already done that, share some pictures so we can help you.
There are a number of things that can be wrong, the brass is only one of them, I would even look real close at the bolt itself to insure there isn't issues there.
SScott
 
#5
Re: Bolt Wouldn't Open!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DocGlenn</div><div class="ubbcode-body">Need some help here. Was shooting my 300 WSM yesterday, shot 12 rounds of 64.5 gr of 4350 (I think, don't have data here) w/ a 165 gr SGK at 2950 fps).

Out of the 12 rounds, I couldn't open the bolt after firing twice. The bolt handle lifted w/o any problems (may have been a little tight, but not enough to really notice), but I couldn't open the bolt after lifting the handle. Actually had to tap it open with a rubber mallet. All rounds were loaded at the same time with the same componets out of the same containers.
I'm assuming these 2 rounds were "hot"? I just really have no idea how the other 10 rounds ejected normally and 2 of them got "hammer stuck". WTF did I do wrong? I'd really appreciate any help I can geton this one. Thanks! </div></div>


If you have any more of those rounds loaded check your shoulder DL to base measurements and confirm your headspace is adequate and that the overall case length of the fired cases are inside the max. case measurements. Get the case specs from a new loading manual.

HTH!
 
#6
Re: Bolt Wouldn't Open!

Got some photos to post:

[img:center]
IMG_0587.jpg
[/img]

[img:center]
IMG_0588.jpg
[/img]

To answer some of the questions:

It was in the mid 70's not hot at all.

The "bad" rounds were in the middle of the firing order. I fired some rounds after the stuck case that ejected normally.

If there wasn't enough headspace would the round have chambered to begin with? Maybe I'm not consedering the proper measurement?

Thanks for any help. I'd really like to find out what I'm doing wrong. This could be a disater if it happened on a hunt and a second shoot was needed.
 
#7
Re: Bolt Wouldn't Open!

Looks like too much pressure to me. The prime has flowed into the FP hole, see the ridge around where FP struck. As to why I don't know what it is about your load in your rifle causing problems, COAL, primer, case volume.....

I had a similar problem. I have a Tikka T3 in 270 WSM and it would show high pressure at the low end of the load with RL22. The rifle just didn't like it. I switched to RL19 a faster powder and problem solved. I still get 3500+FPS with 110gr Vmax
grin.gif


I would try a different powder, a little quicker burning maybe. Look in your load book for a powder that will produce less pressure. I know the Lyman shows pressures.

Good luck
 
#8
Re: Bolt Wouldn't Open!

Your pressure looks fine. The ring on the primer is from the firing pin hole is over sized. The edges of the primers are very round. Also, check your necks. I cant remember right now which WSM it was, but one had a bad problem with thick necks.

How did they feel when you closed the bolt? Tight?
 
#9
Re: Bolt Wouldn't Open!

I had the same problem with my .50bmg. It showed no pressure signs but I could not pull the bolt back. The bolt would open a bit hard but it would not cam open without a tap from a rubber mallet. I chambered the barrel myself and I did not polish the chamber area at all. There are some slight ridges in there that the brass may be getting stuck on. The charge is at the upper limit but not over pressure as far as I can tell. If I back the charge down its fine, however the .50 shoots best right at its max pressure. I going to slightly polish any ridges out and see what happens.
 
#10
Re: Bolt Wouldn't Open!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DocGlenn</div><div class="ubbcode-body">Got some photos to post:

[img:center]
IMG_0587.jpg
[/img]

[img:center]
IMG_0588.jpg
[/img]

To answer some of the questions:

It was in the mid 70's not hot at all.

The "bad" rounds were in the middle of the firing order. I fired some rounds after the stuck case that ejected normally.

If there wasn't enough headspace would the round have chambered to begin with? Maybe I'm not consedering the proper measurement?

Thanks for any help. I'd really like to find out what I'm doing wrong. This could be a disater if it happened on a hunt and a second shoot was needed. </div></div>


I'm no expert on the .50 cal but I don't think this is a pressure issue but a case dimension problem. The tip offs are the primer edges are still really round and show absolutely no flattening or edges on the primers and there is also no gas leakage visible from the primers. The primer cup IMO is not flowing so much as acting like most factory Remington bolts with large firing pin holes and following the path of least resistance into the FP hole.

Were all of these cases full length resized with shoulders bumped and then checked for minimum case length before priming, charging and bullet seating? Is your rifle chamber clean? Do your bolt lugs show any signs of galling or are they smooth on the working surface of the lugs?

HTH!
 
#11
Re: Bolt Wouldn't Open!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: tomme boy</div><div class="ubbcode-body">Your pressure looks fine. The ring on the primer is from the firing pin hole is over sized. The edges of the primers are very round. Also, check your necks. I cant remember right now which WSM it was, but one had a bad problem with thick necks.

How did they feel when you closed the bolt? Tight? </div></div>

I know 25 WSSM has thick neck walls.

Since I was wrong on the pressure guess I think I'm right on this one
 
#12
Re: Bolt Wouldn't Open!

I always do a full length resize on my brass and bump the shoulder back a small amount.

I think the chamber is clean, but I'll do a close inspection to be sure.

Just measured the OAL and it is 2.090 (manual says 2.10) so I'm actually an little short here.

The shoulder measured out to be the same as one of the rounds that ejected normally.

Looks like I may have a neck thickness issue? I've never turned the necks on this brass and it's about time to anneal also. Hopefully, this will take care of the problem. Thanks again for helping me out.

Glenn
 
#13
Re: Bolt Wouldn't Open!

Primer cratering can come from a mismatched firing pin and hole or a weak firing pin spring. It can also be caused by execessive pressure. And looking for primer 'flattening', or not, as a dependable evidence of pressure is vastly overrated.

Combining your stuck cases, itself a sign of very high pressure, with your crated primers suggests you have a significantly excessive powder charge in that load.
 
#14
Re: Bolt Wouldn't Open!

I had this issue once when I was using brass that was 5x fired and only neck sized. The brass grows every firing and sooner or later, you need to bump that back.
 
#15
Re: Bolt Wouldn't Open!

My first guess is a sizing issue. Pressure looks fine.

I had a 223ai that did the same thing. I would neck size until your problem occured and then after a trip through the body die, everything functioned fine. You may need a different FL size die or, just lower yours a little more.

If your die is already making contact with the shell holder, you'll need to grind about 0.010" off the bottom of the die or the top of the holder.
 
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