450 bushmaster problems

[That_FNG]

Got a new 450 bushmaster rifle built and it’s having a problem with the bolt closing. I dropped a dummy round into the barrel and tried to close the bolt but the bolt would only close half way. Pulled back on the charging handle and the bolt is stuck. Had to hit the charging handle with a hammer to get the bolt open. The bolt closes fine on an empty chamber. I can take a dummy round and drop it into the barrel and then the barrel upside down and it will drop out just fine.

thoughts?

 

[Bustedknees]

Plastic dummy round ?
Drop a live round in it..

 

[That_FNG]

Plastic dummy round ?
Drop a live round in it..

It’s a metal dummy round. It’s a federal bullet and brass, just with no powder. Until I know what’s up with it, I’m not comfortable with putting a live round inside it.

 

[GOYABEAN]

It’s a metal dummy round. It’s a federal bullet and brass, just with no powder. Until I know what’s up with it, I’m not comfortable with putting a live round inside it.

Remove firing pin

 

[That_FNG]

Remove firing pin

 

[That_FNG]

I thought about that, but if the bolt get stuck on a live round and then I have to start hammering on the charging handle to get it open again I’m not comfortable with that.

 

[That_FNG]

this is as far as the bolt will close on a round in the chamber. I try to pull the charging handle and the bolt is stuck like this. I have to essentially mortar the charging handle to get it open.

 

[That_FNG]

here is the brass before being loaded in

Here is the same brass after being loaded in.



the case is all scratched up with scratches running the length of it

 

[RooftopKorean]

Not to sound stupid but are you 100% sure there is no defects with the barrel itself? The damage to the brass leads me to think there may be a metal spur inside of it.

 

[Airborneguy]

Lube the SHIT out of everything and try again. I mean really wet it.

I’m going through some issue with my new AR-10 and at my last range session, lubing it like a 70 year old whore got it functioning flawlessly.

New AR’s need rounds through them to work out the kinks. I’ve only had 1-2 that functioned perfectly out the gate.

 

[That_FNG]

Not to sound stupid but are you 100% sure there is no defects with the barrel itself? The damage to the brass leads me to think there may be a metal spur inside of it.

I put a light down the barrel and I could not see anything abnormal in the barrel. The brass only got scratched up when I tried to close the bolt. If I just drop the brass in it goes in all the way no problem. It also falls out freely when I tip the barrel upside down. Something is happen when the bolt try’s to close on a round in the chamber or in the magazine

 

[turbobike]

Pull the upper apart and see if you can hand cycle the bolt in and out the of the breach also check ring seals are not damaged on bolt

 

[dubleuhb]

Are you feeding the round out of a magazine ?
I think it may be getting hung up on the mag.

 

[redtail]

Are you feeding the round out of a magazine ?
I think it may be getting hung up on the mag.

I was just going to chime in on this. Feedlips grab the straight wall cartridge. Some mfg are worse than others, little tweak& polish on the underside maybe.

 

[Twogunwilly]

Are you feeding the round out of a magazine ?
I think it may be getting hung up on the mag.

I second the motion.

 

[dubleuhb]

FUAC model? Makes issues like this more complicated than they have to be.

 

[JamieZ]

Are you feeding the round out of a magazine ?
I think it may be getting hung up on the mag.

What dubleuhb asked and I'll add another question if you are cycling out of a mag,,,is it a Pmag? Ive never had nothing but problems when using Pmags for anything other than 223.

Even my brand new RPR 6 creedmoor doesnt like the manufacturer included Pmag.

 

[That_FNG]

Not to sound stupid but are you 100% sure there is no defects with the barrel itself? The damage to the brass leads me to think there may be a metal spur inside of it.

I was just going to chime in on this. Feedlips grab the straight wall cartridge. Some mfg are worse than others, little tweak& polish on the underside maybe.

not using a magazine at all. Just dropping the round into the chamber by hand and then hitting the bolt release

 

[redtail]

Work the bolt in & out of battery 100 times to work the new off.

 

[That_FNG]

What dubleuhb asked and I'll add another question if you are cycling out of a mag,,,is it a Pmag? Ive never had nothing but problems when using Pmags for anything other than 223.

Even my brand new RPR 6 creedmoor doesnt like the manufacturer included Pmag.

I tried loading one round from the magazines and had the same issue.

I have two asc 450 mags I got off palmetto state.

ASC 450 Bushmaster/458 SOCOM 5 Round Black Marlube Stainless Steel Magazine with Black Follower

ASC's stainless steel magazines are an improvement on a classic, with the highest levels of durability and increased longevity. ASC's magazines are manufactured 100% start to finish in the USA using .

palmettostatearmory.com

I tried with no round in the chambered and pulled the charging handle back and now the bolt has gotten stuck going into battery on an empty chamber.

 

[dubleuhb]

OK, so it's not a mag or feeding problem.
I'm on board with some good lube and working the bolt and see if it gets any better.

 

[That_FNG]

OK, so it's not a mag or feeding problem.
I'm on board with some good lube and working the bolt and see if it gets any better.

I’ve lubed it up soaking wet now and still having the same issue. I’m wondering if the bolt or barrel is out of spec. The bolt is getting stuck going into battery on an empty chamber

 

[Airborneguy]

Brand?

 

[Airborneguy]

Maybe the spring?

 

[redtail]

Not uncommon it seems with 450.
Where did you source barrel?

 

[meketrefe]

Just stop one second.
If you want to make sure first lets measure everything.
The fact that the round drops into the chamber means nothing if the headspace is off.
Before you formed that "dummy" round what was the case lenght after resizing?
Make sure is within OAL spec and just drop an empty shell in the chamber.
Remove the extractor from the bolt and just gently push the bolt into battery.
Very little force should be required.
Also with a sharpee mark the brass mounth edges and around to see if it is being jammed that would indicste a potential headspace issue.
If it closes fine make a dummy round with the same brass but this time coat the bullet ogive with the sharpee. Make sure coal is within spec.
Dont push it too hard, the bolt should rotate into battery wo much force.
If it does not go in send us close up pics of everything, including mesures and any marks and we will guide you with further steps to determine the problem.
Stop lubbing, ramming things, voodoo and prayers. First thing is to make sure your barrel is properly cut and reamed.

 

[That_FNG]

At this point I’m going to throw in the towel with my efforts and take it to a gunsmith

 

[meketrefe]

At this point I’m going to throw in the towel with my efforts and take it to a gunsmith

What I told you is very simple to make sure the chamber is ok. If that does not work we can quickly determine if you need to take it to the gunsmith or whoever the manufacturer.
Everyone should know how to verify headspace for the ammo or reloads they use not just for function and safety but to get more life and performance from the brass/loads.
Straight wall cartriges in autoloaders are a tricky business but it csn be done with sucess.
The msgazines tend to give problems that can be resolved by opening the slips so slightly and/or shortening and deburring them with a dremmel and/or fine file.
Many times the ramps can also use some opening and smoothing/polishing.
Nothing complicated that most people can do unless one doesnt known how to hold a screwdriver, hang a picture on the wall, or replace a lightbulb. In have a cousin who is like that.

 

[meketrefe]

What if it is the actual extractor that is not easily sliding and jamming the mouth into the freebore?
That would explain why it is so hard to extract after you manage to close it.
If you remove the extractor from the bolt then you will know, it takes 2 minutes and also easy to resolve if that is the issue.

 

[Robin]

That was my thought Mek.
Robin