charliemopic
Member
The gun is a Norinco 1911A1 .45 auto.
When my Nork strips a round off the mag it will chamber the round but it will also cause some bullet set back.The more full the mag is the more set back occurs, as much as .040". This will happen with my handloads or factory ammo, ball or HP.
To trouble shoot this I removed the recoil spring, inserted a full or near full mag and slowly pushed the slide into battery. It looks like the when the round takes a slight dip as it is stripped off the mag the nose is too low on the feed ramp which causes the nose to bump the feed ramp and cause bullet set back.
Why is the nose of the bullet hitting too low on the feed ramp?
With rounds in the mag and in the mag well the mag moves up and down or has about .055" up & down play.
I have a mag with a base pad, when I rest the gun on the base pad which holds the mag up into the magwell far as possible bullet set back does not occur.
Measuring this up & down mag in mag well play it looks like .050 to .055"
Mags I have are standard MetalForm 7rd and stainless Kimber ProTac 8rd.This pistol has been to a gun-pistolsmith only once back in the early 1990s when Wilson Combat did a trigger job, sights, barrel & bushing and idunno what else.
The feed ramp appears to be in spec but I am no expert.
I don't have another 1911A1 in front of me to compare.
Is my diagnosis correct?
Has anyone heard of bullet set back and the causes in a 1911A1?
What is the fix?
Thank You For Your Time
-charliemopic-
Edit to change mag up & down play to .25 to .030" and not .055"
When my Nork strips a round off the mag it will chamber the round but it will also cause some bullet set back.The more full the mag is the more set back occurs, as much as .040". This will happen with my handloads or factory ammo, ball or HP.
To trouble shoot this I removed the recoil spring, inserted a full or near full mag and slowly pushed the slide into battery. It looks like the when the round takes a slight dip as it is stripped off the mag the nose is too low on the feed ramp which causes the nose to bump the feed ramp and cause bullet set back.
Why is the nose of the bullet hitting too low on the feed ramp?
With rounds in the mag and in the mag well the mag moves up and down or has about .055" up & down play.
I have a mag with a base pad, when I rest the gun on the base pad which holds the mag up into the magwell far as possible bullet set back does not occur.
Measuring this up & down mag in mag well play it looks like .050 to .055"
Mags I have are standard MetalForm 7rd and stainless Kimber ProTac 8rd.This pistol has been to a gun-pistolsmith only once back in the early 1990s when Wilson Combat did a trigger job, sights, barrel & bushing and idunno what else.
The feed ramp appears to be in spec but I am no expert.
I don't have another 1911A1 in front of me to compare.
Is my diagnosis correct?
Has anyone heard of bullet set back and the causes in a 1911A1?
What is the fix?
Thank You For Your Time
-charliemopic-
Edit to change mag up & down play to .25 to .030" and not .055"
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