Headspace and blown primer

[Trtr0611]

I recently put a Savage pre fit barrel on a Axis receiver. I also replaced the stock with a Boyd’s Pro Varmint. When I installed the barrel I checked the headspace with certified gauges. I got the stock fitted well and the barrel floated. I measured the OAL at 2.853 with a Hornady gauge. I didn’t have any factory ammo but had some handloads at 2.8 OAL. I had fired these loads through another rifle. I also measured the case headspace with a Hornady comparator at 1.625. When I fired the first round everything felt ok but when I went to open the bolt, the bolt slid out about an inch and hung up. The case was still in the chamber and the extractor was riding the rim of the receiver opening and binding up. I took it to a gunsmith and he got the extractor loose and the case was not stuck. He looked it over and put a bore scope in it, checked the headspace and said it looked fine. I know I should have put factory loads through it but I’m stumped why the primer blew out so severely. It blew the case head out so much it won’t fit in a shell holder. It also looks like there is a small mark on the bolt face. I can put up pics later. My thought is maybe the case had too much headspace and slammed into the throat of the chamber causing over pressure. Does 1.625 seem short on headspace? Anybody that loads .243 mind giving input? Thanks

 

[searcher]

I just measured some fired brass out of a factory Ruger .243. It measures 1.624" and was 1.622" prior to firing, as that is how far back I bump the shoulder back on this rifle (.003 - which springs back .001" over a few weeks). So if 1.625 was far too much headspace - I'd then have a short chamber. Seems to me the problem is either A) too hot a load for that rifle. B) Too underpowered with slow powder and unfilled case which can cause pre-detonation C) a problem at the neck where your brass length is excessively long for your new chamber which crimped the bullet creating excessive pressure. I'd also add that your neck might be too small, though unlikely on factory spec chamber. If you are bellow midway on your charge per the manuals - I'd put my money on #B

 

[Trtr0611]

I just measured some fired brass out of a factory Ruger .243. It measures 1.624" and was 1.622" prior to firing, as that is how far back I bump the shoulder back on this rifle (.003 - which springs back .001" over a few weeks). So if 1.625 was far too much headspace - I'd then have a short chamber. Seems to me the problem is either A) too hot a load for that rifle. B) Too underpowered with slow powder and unfilled case which can cause pre-detonation C) a problem at the neck where your brass length is excessively long for your new chamber which crimped the bullet creating excessive pressure. I'd also add that your neck might be too small, though unlikely on factory spec chamber. If you are bellow midway on your charge per the manuals - I'd put my money on #B

Thanks for the reply. The load was a 95g Berger VLD Hunter over 41.0g H4350. That’s right in the middle of Hodgdons guide. The brass was a Federal I believe and I’m not sure how many firings were on it. To be honest it kinda scared me. I’ve never had a malfunction like that and I was afraid I had damaged a brand new barrel. I’m gonna get some factory loads and try again. I may get some unfired brass and load up some fresh loads too.

 

[RegionRat]

Just an opinion on safety.

Depending on your situation... think about disassembling and dumping out any other rounds you loaded in that session just in case that was the wrong powder by accident.

See if those charges are what you thought you loaded. Play it safe till you know what happened. Really sorry to hear this happened.

 

[Trtr0611]

Just an opinion on safety.

Depending on your situation... think about disassembling and dumping out any other rounds you loaded in that session just in case that was the wrong powder by accident.

See if those charges are what you thought you loaded. Play it safe till you know what happened. Really sorry to hear this happened.

Thanks. I’m definitely not going to shoot any more of those loads. I will pull them and dispose of the powder. I plan to start from scratch with full length sized brass with any more handloads.

 

[searcher]

My Berger manual calls for 38.0 to 42.0 of H4350. So you are near the top as far as Berger is concerned - but shouldn't be so hot as to do what your load did. I personally think Berger's loads are maybe more often on the milder side as compared to some of the other manuals. Because you don't know how many loads were on the Federal brass - I might suggest getting some new brass just to rule that out and know what you have. Federal brass is a bit softer than some other brands in my experience. If you have access to a bore scope, I'd check the bore for any obvious abnormalities. It is very possible that you just had a major case separation caused by repeated reloading and thinning of the case just above the web at the base. That possibility alone would prompt me to get new brass. That may be the only problem here.

 

[Texas10]

One possibility is the case mouth was too long for the new chamber, pinching a bullet. Seen it happen on a .243 with almost exactly the same results after the shooter forgot to trim cases. If you have a borescope camera, pull down one of those rounds and chamber the case. Then run your camera down the barrel and look at where the case mouth falls in the chamber.

Glad you weren't hurt.

 

[243winxb]

the primer blew out so severely. It blew the case head out so much it won’t fit in a shell holder.

Use starting load of 38 grs and work up. There are to many variations in reloading. Brass volume, power lot to lot difference, bullet hardness/type, tight chambers, and COL.

Then there is reloader error. Double check every thing, then check it again.

 

[243winxb]

My thought is maybe the case had too much headspace and slammed into the throat of the chamber causing over pressure. Does 1.625 seem short on headspace? Anybody that loads .243 mind giving input?

The Hornady tool is to compare fired brass to reloaded brass. This tool is used to sets Head Clearance, a SAAMI term for slop in the chamber.

Certified gauges are used to set the rifles head space.

 

[jonbearman]

If using a balance beam type scale could you have had it out of level? Or are you using a digital which I always check reading with a balance beam which might be overkill but my face is worth the extra time. What length did you trim your brass too? That can cause bad things to happen like another poster mentioned. Any chance you had the wrong powder AA4350 by accident? There are so many varibles to deal with. Did you measure the bore size? You never know or would realize that someone chambered a wrong caliber in too small a bore like .22 instead of 6mm. That is probably not the problem but food for thought.

 

[Trtr0611]

The Hornady tool is to compare fired brass to reloaded brass. This tool is used to sets Head Clearance, a SAAMI term for slop in the chamber.

Certified gauges are used to set the rifles head space.

View attachment 1173391

I used certified go-no go gauges when I installed the barrel. I was using the Hornady comparator to try and figure out if there was something off with the sizing of the other unfired loads from the same batch.

 

[Trtr0611]

If using a balance beam type scale could you have had it out of level? Or are you using a digital which I always check reading with a balance beam which might be overkill but my face is worth the extra time. What length did you trim your brass too? That can cause bad things to happen like another poster mentioned. Any chance you had the wrong powder AA4350 by accident? There are so many varibles to deal with. Did you measure the bore size? You never know or would realize that someone chambered a wrong caliber in too small a bore like .22 instead of 6mm. That is probably not the problem but food for thought.

I have a digital scale. At the time I loaded the load that went wrong the only powders I had were H4350 and RL17. I’m pretty thorough with checking my loads but I could have overcharged. I did check the diameter of the bore and it measures out ok.

 

[Trtr0611]

After thinking about this I realized that I had neck sized these loads only. The round that blew was loaded for a Tikka. It was loaded rather long....2.80 OAL. I’m not positive of the case length but the unfired loads from the same batch were trimmed to 2.030-2.035. The length of the fired case was 2.025 which seems rather short to me. Back to the OAL.....the new barrel with a Hornady OAL gauge measures 2.85. I figure that is plenty of space to not be jammed into the lands enough to cause excessive pressure. I’m going to put some factory loads through it today.

 

[243winxb]

My thought is maybe the case had too much headspace and slammed into the throat of the chamber causing over pressure.

Test shoulder set back using the Hornady compatator. Take a sized case with know head to datum measurement.
Install a used primer. Place empty brass behind extractor. Case head against the bolt face.
Close bolt, pull trigger. Measure the Head to datum again.
Did the firing pin strike set the shoulder back? Shorter head to datum measurement?

The 223 is shoulder is set back .006" in my Axis.

 

[bsekf]

What happened with the factory loads?

 

[Trtr0611]

Test shoulder set back using the Hornady compatator. Take a sized case with know head to datum measurement.
Install a used primer. Place empty brass behind extractor. Case head against the bolt face.
Close bolt, pull trigger. Measure the Head to datum again.
Did the firing pin strike set the shoulder back? Shorter head to datum measurement?

The 223 is shoulder is set back .006" in my Axis.

I’m not sure I understand. I tried this and it measured the same before and after.......1.620. The only difference I could see is that the old primer is concave now.

 

[Trtr0611]

Just an update.....I took the extractor out of the bolt and checked the headspace again. It is good with the go - no go gauges. I’m gonna try to send some pics.

 

[Trtr0611]

 

[Trtr0611]

The top pic is the federal brass that blew the primer compared to a normal de-primer brass. The second pic is the bolt. Doesn’t look like any major damage. The third pic is the scratch left on the receiver where the extractor blew out and hung the bolt. It had been fixed back to normal in the pic.

 

[Webster]

The top pic is the federal brass that blew the primer compared to a normal de-primer brass. The second pic is the bolt. Doesn’t look like any major damage. The third pic is the scratch left on the receiver where the extractor blew out and hung the bolt. It had been fixed back to normal in the pic.

The bolt looks severily damaged to me. Are the black areas carbon or pits? Has to be hot loads.