Broken Extractor

[Azgeek]

Dusted of my old J&T/Double Star Grendel and shot it for the first time in a couple of years. Broke the extractor. Bolt is fine otherwise. I'm shooting Amex 123 with 28.5 grains of 8208. I was reading through some recent threads where members were saying that might be too hot. This use to be the default go to load about for a lot of guys if memory serves me correctly.

Two questions. Is there a correlation between my load and the broken extractor? It happened once before but thought that had to do with the crappy PPU brass I was reloading. Where can I source a replacement extractor? Rest of bolt appears to be fine.

Thx.

[rwh]

You can get an extractor here, https://secure.wf-api.com/www.precis...extractor.html. Might want to email and ask to make sure you get one that fits.

The load data from Hodgdon gives 82.5 gr of 8208 XBR as a max load. Published load data is thought to be conservative but the actual pressure depends on other factors like temperature, primers, seating depth and case capacity. You need to look carefully at your cases and decide for yourself whether you see pressure signs or not. Two broken extractors is unusual. Your rifle is probably telling you something.

[Klem]

Difficult to answer this question without knowing the cartridge OAL and conditions like the temperature and the dimensions of your chamber.

Both Hogdens and ADI list exactly the same pressures, start and max powder loads for the 123SMK. The SMK is used on the ADI site while Hogdens does not list a specific bullet manufacturer. Even though the AMax and SMK are the same weight different bullet shapes, absolute diameters and bearing surface friction will show different results in peak pressure, muzzle pressure and velocity.

Regardless, Quickload lists both the 123SMK and 123AMax at 28.5/8208 SAAMI OAL 2.25" at way over the SAAMI max peak pressure for this cartridge. The computer simulation displays this load as 59,715lbs of peak pressure for a calibre designed to operate at 52,000 lbs. Quickload is notoriously conservative however so take all this into consideration, along with carefully inspecting your spent cases for signs of over-pressure (e.g. flattened primers and primer flow).

As the powder, load and bullet is right on the cusp of being compressed small changes between loads can be dramatic.

One broken extractor might just be unlucky. Two broken extractors is no coincidence.

Have you done much load development with the 123AMax?

[LRRPF52]

If the extractor is not made from tool steel, not heat treated properly, and made too thin like with a .124" bolt face depth, chances of losing the lip are high.

I personally don't use 8208XBR for anything more than 107gr SMK in the Grendel, after looking at the various sources of pressure data on it, and concluding that it is an optimum powder for 100gr, but is quite fast for 120gr and higher.

What bolt face depth do you have OP?

[VASCAR2]

If it is J & T I'd bet .136 which is what came with my 16" J&T, supposed to be 6.5 Grendel chamber. My extractor was gouging cases pretty good so I polished the extractor and radiused the ejector. Seems to have helped.

[Azgeek]

Regarding this incident, my brass is brand new lapua, cases look good, primers also look good - maybe just a tad on the flat side. Exactly were one would stop for a max load. Chrono reading with a ver 2 magnitospeed at muzzle is 2534. Temperature at the time of malfunction was about 88 and raining. COL=2.250

The last time this happened was about a 1000 rounds ago with PPU brass and full blc-2 charges. Both bolts extractors were from AA. I know that for sure. In both cases just the tip of the extractor that grabs the brass broke.

I have purchased but not tried cfe223 with the amax 123's yet. I may just give the Smk 107 a try!

[Azgeek]

Don't know how to measure a chamber or bolt face so can't help with that info.

[rwh]

If you have calipers you can measure the depth of the bolt face directly. If you don't have calipers you should stop reloading until you do.

[Klem]

Agree with 52' regarding 8208 for the lighter projectiles only.

The 107SMK works well with 8208. 28.5gns of 8208 with the 107SMK has been mentioned here many times.

Extractors from the same manufacturer...

[Azgeek]

If you have calipers you can measure the depth of the bolt face directly. If you don't have calipers you should stop reloading until you do.

Of course I have a mic. If the process is as simple as just using the straight edge, extruding part of the mic and laying the base oacross the lug face, then I got .136 to the bolt face.

[VASCAR2]

Just curious Azgeek, what barrel length J&T do you have. J&T sells Stainless Steel, chrome moley and chrome lined, which do you have?

[terrywick4]

it is as simple as that to measure the bolt face, you have a type 2 6.5 Grendel bolt. Not sure how he got from how you were not sure how to measure it to you don't have a caliper.

Of course I have a mic. If the process is as simple as just using the straight edge, extruding part of the mic and laying the base oacross the lug face, then I got .136 to the bolt face.

[rwh]

Sorry for the part about calipers. I didn't understand what you meant about not being able to measure the depth.

[Azgeek]

No reason to apologize rwh. Thank you for taking the time to help me out. Guess I should have indicated that I did not know the method to make that measurement. My Bad.

I purchased the gun new back in Sept 2008 from CenterFire Systems. Its a 20" steel barrel made by Shaw I believe. There were not a lot of options back then. When I said I was dusting off the Grendel I was not joking! I a bit behind the times.