ejection problems

Talk about the AR15 style rifles chambered in 450 Bushmaster.

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ejection problems

Postby kfbrown14 » Sat Jul 22, 2017 8:01 pm

hello all fellow members. I am brand new to the sight. so here we go with my first and only concern( at this time anyways) I havre built myself a 450 bushmaster with an ar stoner side charging upper, an ar stoner 18 inch barrel, aero lower, a full length buffer tube, a nickel boron 450 bm bolt and if I remember right an aero bcg and the real kicker a jp enterprise captured buffer spring. I have tried several different levels of spring and whatever I used it seems to not eject properly 2-3 per times per mag full (7 shots) every time its the same thing the empty will get caught between the bolt head and the chamber sticking out case opening first 90 degrees right. my first thought is to fast of a cycle? anyone agree? heavier buffer maybe? do I have to get away from the captured spring? fyi about buffer its a gen II 3 weights and I have the alternate spring kit anyone use one of these in their BM?
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Re: ejection problems

Postby Gtek » Sun Jul 23, 2017 8:50 am

How far are the ones going that are being ejected? Gas block alignment? Sounds under gassed to me.
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Re: ejection problems

Postby Bmt85 » Sun Jul 23, 2017 1:27 pm

AR Stoner makes 450B barrels? What gas length system, I'm just curious.

Anyway,take a look at the rims of the spent cases and check gas block alignment. Also, do a quick check of your extractor and ejector springs. If they have weak springs, they could cause issues. I'm also thinking your undergassed, but need more info.
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Re: ejection problems

Postby TonyRumore » Mon Jul 24, 2017 5:43 pm

It's either your extractor/spring or you have one of those Aero uppers where they only opened up the front half of the ejection port.

Tony
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Re: ejection problems

Postby kfbrown14 » Mon Jul 24, 2017 11:19 pm

first thanks for the replies and also NOT an ar stoner barrel , brain fart on my part the ar stoner barrel is on my 6x45. I will double check the 450 barrel maker.. the brass that does come out lands about 1 oclock about 3-5 feet from the muzzle so basically being pushed forward once they come out of ejection port, the side charging upper has a nice big ejection port it has a rifle length gas system my load is hornady 250 tipped with 34 grains alliant 2400 ya I know not a lot of people use the 2400 if they do they seem to keep the data off the net!!
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Re: ejection problems

Postby kfbrown14 » Mon Jul 24, 2017 11:23 pm

as far as the springs in the bolt they are new as is the bolt itself so do I just go to a heavier set of springs??
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Re: ejection problems

Postby Bmt85 » Tue Jul 25, 2017 1:56 am

So not an AR Stoner barrel, but it's an 18" w/ rifle length gas system? Double check that it's not a mid-length gas system. If it is a rifle length gas system, that's your issue.

Also I don't think the 2400 is helping
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Re: ejection problems

Postby Hoot » Tue Jul 25, 2017 4:35 am

kfbrown14 wrote:first thanks for the replies and also NOT an ar stoner barrel , brain fart on my part the ar stoner barrel is on my 6x45. I will double check the 450 barrel maker.. the brass that does come out lands about 1 oclock about 3-5 feet from the muzzle so basically being pushed forward once they come out of ejection port, the side charging upper has a nice big ejection port it has a rifle length gas system my load is hornady 250 tipped with 34 grains alliant 2400 ya I know not a lot of people use the 2400 if they do they seem to keep the data off the net!!


What Bmt85 said.

2400 is appropriate maybe in bullets less than 200gr in this caliber. The best chance it stands is in a carbine gas system. Not a mid length gas system and definitely not a rifle length gas system and not in hot weather. It will go bang, but there are much better powder choices.

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Re: ejection problems

Postby plant_one » Tue Jul 25, 2017 9:42 am

does it cycle normally with factory hornady 250gr loads?
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Re: ejection problems

Postby kfbrown14 » Tue Jul 25, 2017 11:49 pm

don't mean to sound like such a greenhorn but the gas tube is about 14 inches long . so mid length or rifle? I did some research and from what I can gather not to many 450 bm owners think the captured spring set up is a good fit. I weighed the sled part of the unit and it weighs exactly 3 oz too lite? I think it is so I went through my pile a parts and I went with what I had for now. dpms a2 buffer I took out of a build I did for my brother. I weighed it and it weighed a whopp N 8 oz. i ran out and test fired a couple mags and no ejection failures!!!!! and brass was actually ejecting about 4 oclock from the muzzle. much better!! BUT it felt like it was bottoming out against the buffer tube and after inspecting i found it was. it was hitting the stock retaining screw which was a hair to long so i shortened it a bit. then i took the rubber stopper out of the buffer i found 3 metal slugs and 2 bake o lite type slugs so i took it upon myself
(since i have another just like it) to shorten the back of the buffer the length of one of the slugs so now it weighs around 7.5 oz and is short enough to rid it of the thump at the back of the tube. i do plan to lighten the powder charge a bit i was getting 2250 fps second with good groups Too hot? it was just a bit faster than the factory hornady with the same bullet. so i will make up a few different loads and go shoot it with my make shift buffer. almost forgot i put in a david tubb flatwire spring i also had i do have lil gun bl-c2 and some h110 i wanted to use and stick with the 2400 cuz i got like a hundred lbs of the stuff ok more like 10 but still a lot but i want it to shoot and shoot well thanks again for the replies i will update the process tomorrow
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