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Ok I built a 121/2 pm barrel with Gibbs side charge upper. Used a BCM bolt carrier and put in one of 2 new group buy 6.5 bolts. Put in one loaded rd with new star line brass and bolt wont close. Pulled it back all the way and let it go, nope. Remove loaded rd and put in new unprimed case and closed bolt, no go. Pulled bolt back all the way and let it go and it almost closed. Pulled bcg out of my out of my other 6.5 with about 300rds on the same kind of bolt. Let it go from all the way back and it closed. Put in a loaded rd and slammed it home and it closed, so I put in mag with 4 rds and tried to fire it. Boom. It worked and so did the next 4 and bolt stayed open. Switched back to new bolt and bcm carrier and had to let it go about 3 times finally closed so I put mag in and same thing it went boom and cycled perfectly. Today I cut of 2 coils on extractor spring. Still same problem. Whats up Doc??
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Im confused by your switching back and forth. Did you try the bolt that has worked in the bolt carrier that hasn't?
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05-05-2021, 02:30 AM
(This post was last modified: 05-05-2021, 02:33 AM by okiecat.)
Sorry. The bolt is the problem. I think its the extractor sticking out into bore too far and wont go over rim. I am using a standard wt buffer and a Strike flat spring. The switching is a complete bcg that works but also has the group buy bolt in it. I think Im going to order some new extractor clips or whatever they are called and see if different shape or size. Also now matter what I try it still wont chamber and close from the mag, has to be single rd dropped into chamber and them let the bolt fly.
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Try this forum thread, use the link to Johnny's reloading bench for a good take on how to modify the extractor.
https://www.65grendel.com/forum/showthre...tor+polish
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okiecat Wrote:Sorry. The bolt is the problem. I think its the extractor sticking out into bore too far and wont go over rim. I am using a standard wt buffer and a Strike flat spring. The switching is a complete bcg that works but also has the group buy bolt in it. I think Im going to order some new extractor clips or whatever they are called and see if different shape or size. Also now matter what I try it still wont chamber and close from the mag, has to be single rd dropped into chamber and them let the bolt fly.
I had this problem once and it was the wrong extractor. Best I could tell it was an extractor for a 223 / 5.56.
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Pull the extractors of the two bolts and compare them. If one is different, it should be obvious.
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I don't know what the group-buy bolts are exactly, but if you want to try a different extractor, or just get one to serve as a spare, you might buy one of these:
https://www.blackriflearms.com/-65-Grend...p_297.html
These are known to be the best type available, currently.
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Remove the oring from under the extractor and see if the problem is still there. Do this before spending money.
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Have you tried the new bolt in the old barrel to isolate that it is indeed the bolt? You would just need to see if it locks down on empty brass.
Let's go Brandon!
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Ok. All good ideas to isolate the culprit. Will try all of them in the order that seems logical. Maybe tomorrow night or Sat. Thanks and stay tuned for results.
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ok. Got off early, yea. So I tried my bolt and carrier that works in my 20 grendel and it will close with full slam but wont pickup one from mag and close. So I took my group buy bolt that wasnt working and removed extractor and pulled the o ring. Put back in its bcg and it closed with full slam. Loaded up a mag and It closed!!!! So I fired a couple of rounds and they are piling up at 1;30. Adjusted Superlative gas block for a little more gas. Shot 1 more no change. Decided to clean barrel, its new. Couldnt get bolt open. Rubber mallet peck and it opened and ejected case with no bullet and no powder. Yep the powder is in chamber. Bullet stuck in rifling. This is an 85gr pill oal 2.100. No way touching rifling. Must be hammering that bolt back in to battery hard. Is this under gassed or over. Standard buffer and spring. Gas block set about midway.
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05-06-2021, 11:31 PM
(This post was last modified: 05-06-2021, 11:39 PM by 37L1.)
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Yep. Went back and cleaned everything up. turned block all the way closed them 4 1/2 turns open, then 1/2 turn closed. Shot it with a 123gr bullet, Oh forgot Im running a 7 Thunderbeast. So it put brass at 1;30 and held open bolt on empty mag. Turned it in 1/2 turn again and shot, brass at 1;30 and no bolt hold open. Run out of time. Tomorrow going to keep dialing it in 1/2 turn at a time till something starts to work right. Thanks to all again for reading and replying. Us old rookies need a lot of help!
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"Yep the powder is in chamber. Bullet stuck in rifling. This is an 85gr pill oal 2.100. No way touching rifling."
Actually there is a way that it can touch the rifling. If the neck tension of the case is not enough, when the bolt slams home the momentum of the bullet can have it leave the case and enter into the lands.
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Have you checked your seating depth with a comparator? My JP had a tight chamber and I had to do the Sierra 85s at 2.05. They are extremely stubby. If you don't have a comparator, make a dummy (just brass and a bullet) and see what happens. I always do that even after checking with a comparator.
Let's go Brandon!
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05-07-2021, 02:36 AM
(This post was last modified: 05-07-2021, 02:39 AM by okiecat.)
Yes I know. Thats what happened but I checked neck dia of new case and loaded rd. Shows I should have .003 grip. but I can put the bullet back in that neck with my fingers at least .250. This is new Starline brass. I did not size it before using though. But new unloaded ones are tight. Yes I always check every kind of bullet I might try and record in little black book. Have a page for every barrel. It showed 2.250.
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If your cases are landing at the 1:30 postion your perrty badly overgassed.
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Your load for a 123 bullet is much different than for a 85. Test it with the 85.
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The saga has come to an end, I think. So today with the wind breezing at 40, I loaded up 29.8gr/H-335 with 90gr TNT. Cleaned barrel and adjusted gas block down to full close. Opened it 2.5 turns, loaded one rd in mag and shot. Landed at 1:30 and held bolt open. Turned in 1/2 and same thing. Turned in another 1/2 and about 2:00. Turned a 1/4 and landed about 3:30 but didnt hold bolt open. Opened 2 clicks and landed about2:45 and bolt opened and felt soft shooting. It seams to be pretty touchy on the gas block. But for now thats where its staying and thats the bullet Im going to shoot. I will be working up load on up to 31.6 with chrony and grouping. I learned a lot on bolts and gas blocks. Ive got a 300blk that needs this same procedure. Thanks to all. I like this cartridge and this web site.
