Barrel issue

[koden]

I had a new grendel built for my by a local shop a couple months ago. They used an 18" fluted BHW barrel. I have been chasing down a reloading issue.

These 5 rounds were fired through the barrel. They were factory Hornady 123 Amax rounds.



The center case has a noticeably larger bulge at the base than the other 4. It measures 0.4405" at the bulge. I have shot 150 rounds of new hornady brass and I can only use about half of what gets fired. Any brass that is fired in my barrel that measures over 0.4395" at the base is too large to resize. I have 2 sets of Hornady dies and a Sheridan case gage. Any brass that is over 0.4395" has to be run up into the die so far that the shoulder gets pushed back too far to safely shoot. I can not resize the brass using either of my Hornady dies. The bolt measures .135" and the barrel is a type 2 barrel. I tried to chamber a round using a type one bolt and it would not close.

I tried to call Andy on thurs and friday and sent emails but I guess he is out sick. Can someone else help me out here?

Thanks
Mark

[GLSHOOTER]

The print I found on the 6.5 shows .4433 at the wides near the and .4323 at the shoulder. I just measured five fired 243 LBC, Lapua/AA brass, out of my chamber at .4418. I'm using Redding type S Full Length Bushing dies and they are loading easily.

My gut level feeling is that your dies are really undersized. Also Hornady brass is much softer than the Lapua. I wonder if the loads are pretty hot from the factory and it is a combination of two or three things.

Perhaps Ritch will chime in as my 264 is has not been shot at this point. I'm sure this issue can be worked out.

Greg

[koden]

Would the bulge in the center round not concern you? Is that normal?

This is my second Grendel and second BHW barrel. I never had any issues with the first. I just set the dies up to contact the shell holder and then another 1/4 turn and everything sized and chambered perfect.

I never saw that type of a bulge with my other grendel (nor with my 260 or 223 AR's). To me that case looks like it will get head separation if fired again.

I'll go do some more measuring of my resized brass.

[GLSHOOTER]

Jan 13, 2013 14:56:13 GMT -8 koden said:

Would the bulge in the center round not concern you? Is that normal?

This is my second Grendel and second BHW barrel. I never had any issues with the first. I just set the dies up to contact the shell holder and then another 1/4 turn and everything sized and chambered perfect.

I never saw that type of a bulge with my other grendel (nor with my 260 or 223 AR's). To me that case looks like it will get head separation if fired again.

I'll go do some more measuring of my resized brass.

DO NOT set those dies on the shell holder. That will almost always cause excessive sizing. That will cause what you are seing on your next loadings. This will CAUSE a case separation.

You need a headspace measuring tool to make sure you do not move the sholder more than about 0.005 as a MAX. I go 0.003 to 0.004. The big one would be for making darn sure it runs on a big hunt like a Coyote Contest.

Greg

PS: A PIC to folow.

[koden]

The sheridan case gage has a min and max head space cutout on it and I measure every round.

[koden]

Jan 13, 2013 15:09:57 GMT -8 GLSHOOTER said:

That will cause what you are seing on your next loadings. This will CAUSE a case separation.

The rounds above were not reloads. The barrel caused the bulge not me.

[GLSHOOTER]

Those gauges may well give you as much as 0.010 variation in your "acceptable lenght. I prefer a bit more exact measuring in my ammunition.

Here is a BCG that decided to disassemble. This as TYPE I chamber with a TYPE II bolt. The case was new AA that had the shoulder set back about 0.005 giving a shoulder head space of 0.020. This amount is possible given that some dies really move the shoulders and the original new case are on the minimum size. I moved the shoulder a tad necking it down.

This was a 243 LBC case. I'll have to get a picture up and you can see where the unsupported head blew out. The BCG came apart exactly as designed according to the guy that runs a very well known parts manufacturing business here in Phoenix.





This same set up has run about 500 rounds of the previous batch of casings. I suspect the first batch was a bit softer and let the cases stretch out and fire form. Of the five fired before the blow out three showed a possible starting case head separation.

The bolt was fine and the barrel is still sub-MOA at 500 yards. Needles to say I got that TYPE I bolt stuffed in that puppy now!!

Greg

[koden]

Yes, I understand what can happen. The Sheridan gage gives you 0.005" of acceptable head space margin (as measured with my Mitutoyo calipers).

Lets forget about reloading and once fired brass.

The barrel is a type 2 barrel, the bolt is a type 2 bolt. The 5 rounds fired in the original post were FACTORY AMMO. Not factory brass that I loaded. It was Hornady Factory 123 amax ammo. A type 1 bolt will not close on FACTORY grendel ammo and my type 2 bolt measures 0.135" so there should not be any slop due to the bolt.

So what is causing the factory ammo to bulge?

I originally thought it was my reloading too. That's why I ran factory ammo through it.

[GLSHOOTER]

I knew you weren't talking reloads in this instance. But when you mentioned cranking the dies down to the shell holder on other ones it raised some concern.

I wouldn't find the cases you shown to be excessive and would not hesitate to load them. I would want a measurement as to how much shoulder movement you are getting on those factory rounds if I were encountering difficulties.

Most Hornady stuff is not going to be an issue as to pressure historically. I know it is hard to experiment but a different brand of die, like the Redding, might be the ticket on this one. I have loaded quite a few 243 LBC cases using 6 PPC dies but the area for the bushing is too small to run a 6.5 up in them and get it done. Of course I was not sizing all the way down to the shell holder by any stretch but the cases slide right in the chamber even not going all the way down.

If these were in front of me I would size down enough to move my shoulders and see if the cases would chamber easily. If they did I would load up five and go shoot them. I would then bring them home and do it again. I bet that after 10 firings my concern would be taken acre of.

I've mentioned this to Ritch so maybe he can pitch in.

Greg

[koden]

I went out and and backed the dies off. I marked a case shoulder with dry erase marker to find out what depth the dies start contacting the shoulder. They touch the shoulder when the shell holder just kisses the bottom of the die.

I'll see if I can find a non-hornady sizing die and see if that makes a difference.

I really dont want to get rid of this barrel. It is ragged hole accurate at 100 yards with 28gr of TAC.

I hope it is my reloading error or a problem with the dies.