9mm AR BCG: Glock style bs Colt pattern
- Thread starter krw
- Start date
A Glock Pattern bolt PCC , feeds from a single stack at the feed lips of the magazine... and needs to clear the Glock mag profile at that point.
A Colt Pattern bolt feeds from a double stack at the feed lips... so the portion of the bolt that pushes the casehead of the cartridge into the chamber will be wider.
From here....https://www.ar15.com/forums/ar-15/Collt-glock-cut-bolt-difference-/15-738388/
Quote... "Here is a photo I took some time back to illustrate the difference in the bolts.The left two bolts have been 'Glock cut'. The bolt on the right is an original from a Colt Model R0635 upper."
There could also be differences in the hammer ramp angle on the bolt.... Original Colt Pattern bolts had a really steep angle, so steep, that the cocking of the hammer , with that steep angle, was hard on trigger pins.
However... the steep angle allowed for proper Hammer reset from the longer flat part of the bolt.
Lots of modern 9MM PCC's can have hammer reset issues, because the ramp has been made shallower... and unless a USGI profile hammer was used, sometimes the hammer wouldn't reset far enough.
The "fix" was , to make that ramp / straight area press the hammer down slightly more ( more "depth on the bottom / smooth part... achieving better / proper / consistent hammer reset.
There is a lot more to the differences... but I am tired, and going to sleep.
I am sure others will add to the differences.
I hope I understood your question.
Oops, this pic shows the added material after a shallower ramp angle... the step helps positive hammer reset.
A Colt Pattern bolt feeds from a double stack at the feed lips... so the portion of the bolt that pushes the casehead of the cartridge into the chamber will be wider.
From here....https://www.ar15.com/forums/ar-15/Collt-glock-cut-bolt-difference-/15-738388/
Quote... "Here is a photo I took some time back to illustrate the difference in the bolts.The left two bolts have been 'Glock cut'. The bolt on the right is an original from a Colt Model R0635 upper."
There could also be differences in the hammer ramp angle on the bolt.... Original Colt Pattern bolts had a really steep angle, so steep, that the cocking of the hammer , with that steep angle, was hard on trigger pins.
However... the steep angle allowed for proper Hammer reset from the longer flat part of the bolt.
Lots of modern 9MM PCC's can have hammer reset issues, because the ramp has been made shallower... and unless a USGI profile hammer was used, sometimes the hammer wouldn't reset far enough.
The "fix" was , to make that ramp / straight area press the hammer down slightly more ( more "depth on the bottom / smooth part... achieving better / proper / consistent hammer reset.
There is a lot more to the differences... but I am tired, and going to sleep.
I am sure others will add to the differences.
I hope I understood your question.
Oops, this pic shows the added material after a shallower ramp angle... the step helps positive hammer reset.
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