Bolt sticking

Talk about the AR15 style rifles chambered in 450 Bushmaster.

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Bolt sticking

Postby Jmeier1981 » Tue Dec 04, 2018 10:44 pm

So our deer season opened last Saturday the 1st. Two of us shooting 450s had an issue a couple times where the BCG would get stuck... It was always a live unfired shell, loaded the mag put it in the magwell and hit the bolt release but then when the hunt was over we absolutely could not unload that live round with the charging handle... Had to actually fire the gun to get it out. Any ideas why? This is the 3rd year Ive had mine and never had an issue until this weekend and not just mine but another one having the same issue seemed weird to me.
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Re: Bolt sticking

Postby Al in Mi » Wed Dec 05, 2018 3:58 am

What ammo, factory or reloads?
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Re: Bolt sticking

Postby Jmeier1981 » Wed Dec 05, 2018 6:46 am

Factory Hornady FTX and also some 250g XPB reloads
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Re: Bolt sticking

Postby Al in Mi » Wed Dec 05, 2018 8:46 am

my first guess would be dirty chamber or gunk behind the lugs of the extension
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Re: Bolt sticking

Postby TonyRumore » Wed Dec 05, 2018 4:12 pm

About the time Hornady introduced the Black ammo, they started making the cases a hair longer. Before that, they were actually too short and created excessive head space issues. Remember the light primer strike issue on earlier Bushmaster uppers? Bushmaster had the chambers a bit too deep and the brass was too short. It's possible your chamber is cut a hair short. It would work with the old brass, but jam up the works with the newer longer brass.

Tony
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Re: Bolt sticking

Postby Jmeier1981 » Wed Dec 05, 2018 9:05 pm

TonyRumore wrote:About the time Hornady introduced the Black ammo, they started making the cases a hair longer. Before that, they were actually too short and created excessive head space issues. Remember the light primer strike issue on earlier Bushmaster uppers? Bushmaster had the chambers a bit too deep and the brass was too short. It's possible your chamber is cut a hair short. It would work with the old brass, but jam up the works with the newer longer brass.

Tony


Had the same issue on 2 different guns, different makers as well... One was a 20" Bushmaster complete upper the other was a piece together build with a 16" Bear Creek barrel. Neither of them have had this issue prior to last weekends hunt.
Both guns were shooting both the 250g XPB reloads and also factory Hornady black FTX
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Re: Bolt sticking

Postby Al in Mi » Thu Dec 06, 2018 7:27 am

next time it happens, you might want to try pulling back on the charging handle and tapping to butt on a bench or tailgate or ground, shouldn't take much to dislodge it.

then look at the case, see if there are any shiny spots around the case mouth, or maybe heavy scratches along the case that may cause the sticking. Mag lips and barrel extensions are notorious for sharp edges.

also check your bolthead for a cracked or burred lug
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Re: Bolt sticking

Postby Bmt85 » Thu Dec 06, 2018 9:54 am

Al in Mi wrote:next time it happens, you might want to try pulling back on the charging handle and tapping to butt on a bench or tailgate or ground, shouldn't take much to dislodge it.

then look at the case, see if there are any shiny spots around the case mouth, or maybe heavy scratches along the case that may cause the sticking. Mag lips and barrel extensions are notorious for sharp edges.

also check your bolthead for a cracked or burred lug


This. It's called mortaring. Make sure you do it right, you can run the risk of destroying your lower receiver.

Al has another good point, check the bolts.

To your issue, it sounds like out of spec ammo. If you've had it for years and this is the first problem, and it's choking another gun and the same time, it's probably the ammo.

What lubes are you using in the rifles, and what was the temp?
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Re: Bolt sticking

Postby Bmt85 » Thu Dec 06, 2018 9:55 am

TonyRumore wrote:About the time Hornady introduced the Black ammo, they started making the cases a hair longer. Before that, they were actually too short and created excessive head space issues. Remember the light primer strike issue on earlier Bushmaster uppers? Bushmaster had the chambers a bit too deep and the brass was too short. It's possible your chamber is cut a hair short. It would work with the old brass, but jam up the works with the newer longer brass.

Tony


First I've heard of that. Good to know.
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Re: Bolt sticking

Postby Hoot » Thu Dec 06, 2018 11:05 am

Bmt85 wrote:First I've heard of that. Good to know.


Ditto.
In Theory, there is no difference between theory and practice. In Practice, there is.
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