Grendel Bolt measures .138

[MTNmyMAG]

You may have seen my other thread on the issues I have had with my Rifle and high pressure signs at under max charges. I measured my bolt face depth again today and came up with .138. I assume .002 over length could cause the primer signs I am seeing. I am not sure the manufacture of this bolt is there any known example of my issue from 2 to 3 years ago?

[PigOPs]

I'll take a stab at this and will be corrected if wrong. One thing to consider when measuring your bolt face is that the lug length factors in as well. For example, my bolt measures .134" and my lugs measure .277" your lug length determines how far into the barrel extension the bolt locks in, which I believe could change headspace.

All that being said, I don't believe that .002" could cause too much in way of pressure signs but I suppose it's possible. I'd have to see your primers to know to what extent they are flattening. I do believe, however, that primers can be flattened by excessive headspace.

[LRRPF52]

The funny thing about primer signs is that they are a terrible indicator of pressure. I'm reading this old reloading handbook from 1936, where they have a graph of three series of case heads with primer indentations clearly visible after the cartridges were fired.

They were using a radial pressure test gauge, which was common for that era. Anyway, they document how even uncharged cases showed flattened primers.

Some primers on 70,000psi loads look just like the primers on 50,000psi loads, while one of the 70,000psi loads blew the primer entirely out.

[MTNmyMAG]

I am piercing primers with hotter loads and swipe marks on brass

[LRRPF52]

Was your bolt face depth checked when you got it?

Back down if you're seeing these types of pressure signs (pierced primers, brass flow into the ejector channel).

What kind of jump do you have?

[PigOPs]

Also check the overall length of your bolt (It should be 2.810"). If it's too short your firing pin may be protruding too far. Your firing pin tip needs a good look too. Usually if you pierce a primer there is damage to the firing pin that could cause subsequent issues.

[MTNmyMAG]

Was your bolt face depth checked when you got it?

Back down if you're seeing these types of pressure signs (pierced primers, brass flow into the ejector channel).

What kind of jump do you have?

I have not measured distance to lands but I have made sure I am not contacting. Blackened a loaded round with a magic marker no Contact. I did back down but not happy with 14.5" barrel velocity levels from 24" barrel.

[LRRPF52]

Try CFE if you can find it. It's a very forgiving powder. This is with what pill again?

[NugginFutz]

I have not measured distance to lands but I have made sure I am not contacting. Blackened a loaded round with a magic marker no Contact. I did back down but not happy with 14.5" barrel velocity levels from 24" barrel.

I would seriously consider calling Carl at BHW. He has been very accommodating with many others with barrel issues. More than once, I've read where he's asked for the barrel back to diagnose. From what I recall, he's resolved each case. A real stand up fellow.

[HuntTXhogs]

Did OP say this was a BHW barrel? I must've missed that.

What happens when you put in a .136 bolt?

[NugginFutz]

He did, in a previous thread.

[MTNmyMAG]

I would seriously consider calling Carl at BHW. He has been very accommodating with many others with barrel issues. More than once, I've read where he's asked for the barrel back to diagnose. From what I recall, he's resolved each case. A real stand up fellow.

I have not contacted them, I got this barrel second hand new and then had it profiled, so I would not expect them to do anything with it. To the guy that asked I mentioned it was a BHW in another thread.

[MTNmyMAG]

Try CFE if you can find it. It's a very forgiving powder. This is with what pill again?

123's Lapua, Nosler AMAX and SST all same result. I have not gotten any CFE But I did find a lb of Leverlution.

[LRRPF52]

What's bothering me is that you are seeing pressure signs and limited velocity when a polygonal rifled barrel should build pressure slower with the same loads compared to another conventionally rifled barrel.

Let's let BHW cover down on this with you, as I know they have taken care of customers in the past in the event there was a concern.

[HuntTXhogs]

Wait wait wait.

Is this a 6.5 Grendel or a 264lbc ?

Don't even get me started on BHW's Type 1 / Type 2 fiasco

[MTNmyMAG]

It's a 264 LBC

[HuntTXhogs]

It's a 264 LBC

I recently had a bad experience - it went something like this:

A guy traded me a Black Hole Type 1 barrel with a Type 2 (Grendel) bolt which was resulting in too much headspacing based on the deeper bolt face.

Symptoms I was experiencing were:

pierced primers

belting toward the case rim

and in 3 cases out of 45 it laterally tore the case apart (head separation), not fully but 90% separation.

Because the Type 1 barrels with lock up fine with either spec bolt you can begin to see that evaluating a gun at face value isn't going to reveal the true story with the Black Hole Weaponry barrels. Furthermore the ONLY way to verify is to take the barrel out of the gun or if you are super ambidextrious you can take measures of the chamber with a round layed into it, here is a video from BHW demonstrating the issues I experienced

http://www.youtube.com/watch?v=DZncepUMgBg

I put a Model 1 7.62x39 bolt in it and function fired 40 rounds with zero issues.

YMMV - I took the time to uninstall the barrel and work the issue with components in hand.

Are we having fun yet.......

HTXH

[NugginFutz]

Good info, HTXH, but the OP has been down that road, already.

http://www.65grendel.com/forum/showthrea...#post86329

At this point, If I am not mistaken, he is chasing muzzle velocity now, and keeps bumping into pressure signs.

[HuntTXhogs]

Sorry, trying to trace his steps over two threads is beyond my pay grade...

I didn't read that he in fact tried a 7.62 bolt, taking measurements alone,with the barrel installed, won't reveal the issues I relate above.

MmyM - can you confirm that you tried a 7.62 bolt and that it did or didn't go into battery?