1911Forum banner

1 - 20 of 29 Posts

·
Registered
Joined
·
111 Posts
Discussion Starter · #1 ·
I have a couple of Caspian frames with shallow frame ramps and would like to cut them to a depth of .420 or so for reliable feeding of hollow points. Does anybody have a "formula" for figuring out how deep the bottom of the frame ramp can be cut? My understanding is that some frame ramps will work at say .420 while this is too deep on other frames that may only allow .380 or so. Any assistance is much appreciated!

Thanks in advance,
Ben H
 

·
Registered
Joined
·
111 Posts
Discussion Starter · #3 ·
Unramped Barrel

Not a ramped but a standard barrel. Some say "just cut it down until it is just above the bottom of the slide stop window". It seems to me that this might not work for all frames because of tolerances. My biggest concern is moving the top of the frame ramp too far forward resulting in too deep of a barrel throat, after the 1/32" or so gap is reestablished and the barrel throat adjusted.

Thanks,
Ben H
 

·
Premium Member
Joined
·
7,080 Posts
Ben,
Some consider a bed length of .246" length to be the minimum.
Hard dimension to measure. Subject to individual technique.
Hook one leg of the caliper on the VIS on an angle, and eyeball to the top of the ramp.
Some manufacturer's frames have the front wall of the mag well located too far forward. In these cases I might drop the angle to 30 1/2 degrees and settle for a .360" depth.
When a custom smith declines to work on 'such and suches' frames, this might be the reason.
 

·
Registered
Joined
·
321 Posts
I agree with Chuck, but I don't like to push my luck and try to keep the barrel bed to a minimum of .250 where Chuck states the absolute minimum of .246. My experience with the Caspian frames is that at the .250 barrel bed minimum the best you can hope for on feed ramp depth is somewhere betwen .360-.375 depending on the frame while still maintaining the proper angle.
 

·
Registered
Joined
·
111 Posts
Discussion Starter · #7 ·
Thanks!

Chuck & Dwayne;

Thanks for your replies as this is exactly what I wanted to know. I assume that when fitting a new barrel the frame ramp should only be cut after barrel drop timing/clearance has been checked and the VIS moved back (if needed) as this would shorten the length of the barrel bed.

Thanks again,
Ben H
 

·
Banned
Joined
·
672 Posts
My experience has mirrored Dwayne's. Many times, feedramps need to be addressed. This frame was ordered as .45. I think the depth maxed-out around .365".
 

·
Premium Member
Joined
·
7,080 Posts
Interesting.
The Dave Sample online Patriot classes had near 100% reliability success.
Did they modify feedramps?
Big Jon?
 

·
Registered
1911 Pistol smith
Joined
·
464 Posts
Chuck-

Can't speak for all the Patriot frames...mine has a depth of .385ish IIRC. Not sure of the angle can pull out the gun and take measurements off it if needed.

Mark
 

·
Registered
Joined
·
5,089 Posts
FWIW I'm 95% done with my Caspian/Fosters build. The ramp was short and my smith told me he was only about to cut it to .370.

It shoots great but my smith said he would have like to be able to cut it deeper.
 

·
Registered
Joined
·
3,878 Posts
My experience has mirrored Dwayne's. Many times, feedramps need to be addressed. This frame was ordered as .45. I think the depth maxed-out around .365".
This frame looks like my Caspian I ordered in 45ACP. It ran factory Ball okay but reloads & hollow points were not reliable at all. When I switched the upper with a 10mm this ramp ran flawless.
 

·
Registered
Joined
·
1,960 Posts
Is there any gunsmithing "reason" why 45 frame ramps aren't machined to the proper/optimum length on a given frame?
Internet blather to the contrary, the answer is......
No!
But carefully reread the posts above. Certain dimensions must be maintained. Because of that, "optimum" depth on frame A may differ from frame B. Pistolwrench explained why.
 

·
Registered
Joined
·
209 Posts
Internet blather...
Let me a few hours - as I am busy in the real life - I will show you my method to cut a ramp. I don't have any gun on my kitchen table right now, but I will show you drawings
 
1 - 20 of 29 Posts
Top