6.8 SPC Forums banner
1 - 20 of 20 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter · #1 ·
So finally got to fire about 200 rounds on my build last week @ Pala shooting range. Had some issues tho with casing not discharge after firing the round. I have to use the charging handle to clear before taking the next shoot. I do have an adjustable gas tube which I did open up so give it more gas. But still got the same result. I had talked to some and they think it’s my buffer spring. Has anyone had this same issue or have advice?
 

·
Registered
Joined
·
1,037 Posts
Make sure you don't have a sliver of brass under the extractor. It's not uncommon for new builds to shave a little brass until the components get smoothed out and they can end up in some strange places.
 

·
Registered
Joined
·
4,803 Posts
I've never had an issue with the buffer spring in any of my builds. Was it factory ammo or handloads? A round that has high chamber pressure can hold the case in the chamber during extractions.
 

·
Registered
Joined
·
4,803 Posts
There would not be a readily apparent indication of high chamber pressure holding/delaying extraction except the brass comes out cloudy (loses its shine).
 

·
Registered
Joined
·
1,260 Posts
Sounds to me that it is not getting gas through the adjustable gas block.
 

·
Registered
Joined
·
4,803 Posts
Good post, Strawdawg. That is always to first build aspect to check but easy to miss. When installing a free-float handguard, the gas block has to leave room for the forward handguard plate even when it is not installed.
 

·
Registered
Joined
·
1,061 Posts
Good post, Strawdawg. That is always to first build aspect to check but easy to miss. When installing a free-float handguard, the gas block has to leave room for the forward handguard plate even when it is not installed.
This is not always true as there are barrel makers out there that place the gas port such that the block should be firm against the shoulder, so it's advisable to measure if you have any doubt.

But, I agree, this sounds like not enough gas is getting through the system to cycle the action and gas block alignment is the first thing I'd check. It sounds like the bolt carrier isn't cycling as if it did and it was just an ejector issue you'd be getting double feeds (e.g., it would still strip off a new round from the mag but the spent casing is still in the chamber).

Yes, this could also be caused by having an undersized gas port, an obstruction in the gas system, too much reciprocating mass for the gas delivered (e.g., a full auto bolt carrier plus a heavy buffer), and/or an excessively powerful spring that is providing too much resistance. Think of it like a balance beam, where you have "gas delivered" on one side of the fulcrum, which is a function of gas port, gas block, and even ammunition, which has to balance with the reciprocating parts on the other side of the fulcrum (BCG, buffer, spring). You have to get these "in balance" for the system to work reliably.
 

·
Premium Member
Joined
·
966 Posts
Who made the barrel that you are using? Wilson is one that tends to be on the low side when it comes to it comes to gas port size with some ammunition.
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #12 ·
Wow, all awesome advice. I will check on all that you all shared. Appreciate all that is being shared. Learning a lot already. My barrel is a Wilson.
 

·
Registered
Joined
·
1,061 Posts
I started using a teslong borescopes to check gas port alignment on new builds. Always good to keep some of the shims around.
All these years and builds and I didn't know that existed. It's a waste of $5 + shipping and tax, though, when a credit card will give you the spacing you need while you affix the gas block.
 

·
Registered
Joined
·
2,030 Posts
Didn't Constructor at one time say to use a dollar bill and it should slide fairly easily between the collar and gas block? Or am I remembering that incorrerctly?
 

·
Registered
Joined
·
1,061 Posts
Didn't Constructor at one time say to use a dollar bill and it should slide fairly easily between the collar and gas block? Or am I remembering that incorrerctly?
That would be a bit too thin. A credit card usually works. There is quite a bit of wiggle room so you eyeball it and usually be fine.
 
1 - 20 of 20 Posts
Top