Odd 300BO jams need opinion

[Drew P]

Testing some 300bo today and got a few jams I’d like opinion on. Empty case somehow got stuck up in the hole on the bolt carrier op handle. Can’t say I’ve had this kind that I remember. Is there an obvious cause y’all can see from here?

These were lil’gun loads with 150gr hitek coated sharp point type pills. I’m not sure how the base of the cartridge could jump out of the bolt face and up like that. Tried two mags.

[jimb16]

3 things to check
1. bad case rims
2. weak or chipped extractor
3. load is a little to light
any of these could cause this problem.

[popper]

SWAG - didn't extract properly. Slip off extractor and the ejector pin pushes out of bolt. Bolt pushes on next case and forces old one up. Side charge upper? No charge handle to keep case down. Neat fibre hand guard & hi end parts.

[Hossfly]

I had many jams with light charge when first started with 300 bo.

[Drew P]

Yes I bet it’s a light charge thanks. I was trying to work up but initial tests with a low end charge seemed to produce some primer flow so I was nervous and lowered it more. But I bet it’s too low.

Yes it’s a side charge bolt but I don’t like it that much so I’m using a standard charge handle in it.

[HangFireW8]

SWAG - didn't extract properly. Slip off extractor and the ejector pin pushes out of bolt. Bolt pushes on next case and forces old one up. Side charge upper? No charge handle to keep case down. Neat fibre hand guard & hi end parts.I agree, though technically an ejection failure, case has extracted OK already. I don't always use the terms correctly either, even coming from a shotgun background I should know better (trap guns usually extract but lack ejectors, to better save shells for reloading).

[popper]

If it is light charge, check the primer, based outside? I use light loads and they usually don't pick up the next rnd.

[Moleman-]

Try putting a #60 o-ring around the extractor spring if the extractor is otherwise fine. They're cheap and you can get them at just about any hardware store in the plumbing section. If that fixes it get a new extractor spring if you want.

[Drew P]

Try putting a #60 o-ring around the extractor spring if the extractor is otherwise fine. They're cheap and you can get them at just about any hardware store in the plumbing section. If that fixes it get a new extractor spring if you want.
Mind=blown! That works?

[Drew P]

If it is light charge, check the primer, based outside? I use light loads and they usually don't pick up the next rnd.


Good point. Primers flattened out. I haven’t Chrono yet tho.

[Moleman-]

Mind=blown! That works?

Yep, it just makes act like the extractor spring is a little stronger. They make much more expensive fancy ones made specifically for this but the bubble packs at home depot/lowes/menards/ace are cheap and work. The better ones are viton, but nitrile will work if you're not trying to get the barrel hot enough to burn off the oil. the last pack I bought from Lowes 4-5 years ago are still working.

[Bodean98]

If your backing your charge down because of primer flow (excess pressure), your problem is not a light charge unless your using a powder that does not like to be downloaded. I am not at all familiar with Lil'Gun and have no experience with it. I think your problem is better described as under gassed.
I experienced that particular jam when looking for a subsonic load. Mine was caused by the bolt short cycling(not enough gas to function properly). Another symptom I had was the bolt would not consistently hold open on the last round. Some times the bolt would catch on the shoulder of the bolt carrier. Try a few single shots with an empty mag installed and see if you have the same problem.
My fix was pretty simple. I had plenty of room to increase the charge and not have pressure problems so that's what I did.
You may need to use a different powder to get yours resolved.

[skeet1]

I had nothing but trouble with jams in my .300 blackout using different brands of GI type metal mags. I then saw a 20 rd. Magpul in the store and thought I'd try it. I have not had a problem since. I'm not saying that this will solve your problem but you might try it. I have not tried the 30 rd. Magpul mags but I would suppose they would work just as well.


Ken

[Gtek]

No Chrony? Not knowing where you are wanting to land, the 300 you may find has little windows of/for operation in an AR. This is in NO way a do all in the AR, playing outside better think about a bolt or single poke. Think I would research your load with the powder/bullet weight and shoot for 1050 FPSish and up and tweak gas to function 100% and call that the bottom. Change anything front end or a can and all bets are off. Welcome to the 300 BO!

[popper]

O ring trick has been used for years, don't they all come with them? Real question is how the base gets out of the bolt pocket. If case is partially extracted, then slips, ejector pin will push it out - returning bolt will hit base and push it up. If case is not HS properly, AND primer pushed out of case, might push base out of bolt pocket. Under gassed usually gives an override jam, more of a stove-pipe type jam. Do the bases have the ejector swipe?