AR Pistol cycling too fast

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1bigrn

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My AR Pistol upper 7.5 " is presently on a rifle lower and it does not want to cycle with the lower. It cycle too fast and catches the brass before it is flung free of the upper. If Im shooting the final round the bolt does catch open, so I do need to slow down the cycling rate.
The AR pistol has a lightened bolt carrier and I'm thinking I can go with a standard auto bolt carrier or could get a heavier buffer or spring?
What everyone's thoughts?
 
Fullauto bolt+ extra heavy buffer like 9mm buffer is what you need.
You don't need heavier springs if you want to slow down the cylic rate.
You want the extra weights keeping the spring compressed longer let the spend brass clear the ejection port, extra heavy spring would be counter productive, in your case.
 
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1bigrn said:
My AR Pistol upper 7.5 " is presently on a rifle lower and it does not want to cycle with the lower. It cycle too fast and catches the brass before it is flung free of the upper.
Click to expand...

It is impossible to catch the brass before it clears the ejection port. What happens is that the extraction cycle starts too early and the extractor does not have enough tension to pull the casing completely clear of the chamber and have it ejected properly.

1. Increase extractor spring tension - extra power extractor spring or O-ring

2. use at the very least H-buffer, and go up to HH or maybe ever H3 if you have the choice

3. use a standard carrier

the o-ring and extractor spring are the cheapest, I will start there.
 
Hunter1970 said:
my 7.5 runs like a top. heavy (FA) carrier and a Spike's ST-2 buffer FWIW.
Click to expand...

This is exactly what I ran in my 6.5 inch 223 before I sold the barrel. Ran great.



greentips said:
It is impossible to catch the brass before it clears the ejection port. What happens is that the extraction cycle starts too early and the extractor does not have enough tension to pull the casing completely clear of the chamber and have it ejected properly.

1. Increase extractor spring tension - extra power extractor spring or O-ring

2. use at the very least H-buffer, and go up to HH or maybe ever H3 if you have the choice

3. use a standard carrier

the o-ring and extractor spring are the cheapest, I will start there.
Click to expand...



^^^ This.
I went with a FA BCG with mine but only because that's what I had. The heavier buffer is all that's really needed but your issue sounds like an extractor issue not a carrier velocity problem.
Once you correct the extractor issue if you notice trigger slap (it resetting so hard it kinda hurts your trigger finger) then you need to slow down the carrier velocity.

Good luck
 
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greentips said:
It is impossible to catch the brass before it clears the ejection port. What happens is that the extraction cycle starts too early and the extractor does not have enough tension to pull the casing completely clear of the chamber and have it ejected properly.

1. Increase extractor spring tension - extra power extractor spring or O-ring

2. use at the very least H-buffer, and go up to HH or maybe ever H3 if you have the choice

3. use a standard carrier

the o-ring and extractor spring are the cheapest, I will start there.
Click to expand...

Green tips is right, the extractor should throw brass well clear the port when the bolt is still going backwards.
 
I was told that if I wanted my 7.5 to run problem free do the extractor
oring upgrade kit, I had a FA bolt, use a heavy buffer, I went T2 and a
decent spring. It works. Regards 375rum
 
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