Hi catbird, I’m a little late answering your question, I down loaded this reply onto a floppy and ½ of it got scrambled, please excuse me if I repeat what was said above or over answered your question. I added a few things that may help in your quest for building an accurate 1911.
To answer your questions: If you tightened-up the tolerances in your pistol, I’m not surprised it will shoot 2 inch @ 50 yards and I don’t think you have a fluke. For what your working with, 2 inch @ 50 yards is pretty good out of a 45 ACP.
Yes, I think you should be able to get 2 inch out of your next pistol, give or take a ½ inch.
I don't think yu need a $1500 pistol to shoot accurately. As you know, you can tighten-up a loosely fitted pistol with a good barrel and do the same thing. BUT! With a new after market frame & slide, CNC machine to exacting tolerances, properly heat-treated, it will retain its tolerances much better in the long run. You will have to justify the cost in fixing-up a loosely fitted pistol or going with a new, tight tolerance platform.
One BIG draw back in building a 1-1/2 inch pistol is the ammo. Most ammo won’t shoot 1-1/2 @ 50 yards out of a barrel test fixture, so its pretty tough to build a 1-1/2 inch pistol with all the variables involved. Remember a little bit of wind will also play hell with your bullets when testing.
First, to test the accuracy, you need good quality match ammo like Federal wad-cutter. For a reload, the Nosler 185 grain is an excellent bullet.
Mike Curtis has fire more ammo through barrel test fixtures than anyone I know. Mike is retired Marine Corps, built bullseye pistols at the Corps and in his retirement. His pistols dominated Camp Perry while he was at the Corps and in decade of the 90’s in his retirement. I’ve worked closely with Mike Curtis for a few years. Before Mike builds a pistol he tests each barrel for accuracy in a barrel test fixture. He’ll tell you if a barrel shoots a 1-1/4 10 shots @ 50 yards your doing pretty good. NONE of the barrel I sent him for testing went below 1-1/4. Now, when you build the gun your going to loose a little accuracy. He feels the ammo is a limiting factor in the 45ACP. Some feel the 9mm’s (38 Super etc…) are inherently more accurate with the right ammo. I believe this is true. Sub-1 inch groups are not uncommon. If you have a 45 that CONSISTANTY shoots 10 shots 1-1/2 inch @ 50 yards, gold plate it.
To wring-out the last little bit of accuracy, 1911 smiths pay special attention to fitting the lower barrel lugs (also referred to as the barrel feet). The idea is to leave the flat that contacts the slide stop pin as long as possible. This is to ensure the barrel stays locked into battery before the bullet exits the muzzle. I recently saw a high-speed film of a 9mm bullet exiting the muzzle in a 1911-designed pistol. I managed to stop the film right at the moment the bullet was about to exit the muzzle, i.e. the bullet was still in the barrel. Before the pistol was fired the full-length guide rod was flush with the muzzle. I could see the full length rod guide protruding (I guessed approximately one 1/16th of a inch) from the slide before the bullet exited the muzzle, meaning the slide was moving rearward as the bullet was still in the barrel. I was told latter that the rod guide was measured @ .093 before the bullet exited the muzzle. The 45 ACP with more recoil will most likely have more movement.
Warning: the flat, link-lug fit is critical. If not fit correctly it will cause problems.
1.Some smiths try to make the flat to long and cut the lugs thin and they sheer off, (as a rule of thumb, I NEVER cut the lugs thinner than .100, measured from the center of the radius at the slide stop pin cut to the rear of the lug).
2. If the flat is to long the link may bind and break going in or out of battery.
3. To eliminate the bind coming out or into battery, I seen smiths grind the bottom of the link pinhole elongating it, i.e. egg shaped, to eliminate the binding. With an elongated or long link the barrel may stay locked into the slide to long and the rear of the barrel feet can hit the frame sheer off.
I cut my lower barrel lugs on a 4th axis rotary table on a milling machine. I have a certain set of dimensions I use to cut the flat and the forward radius (where the link swivels in & out of battery). The center of the set-up is the link pinhole that attaches the link to the barrel, i.e. this pinhole is centered on the table and all other measurements are taken from this centerline. The end-mill I cut the lug with is .198, so when complete my digital read out will tell me what size link is needed. This cut is made in one motion (I’m actually turning 2 axis at the same time) to give me a smooth transition from the flat to the radius. It is critical that there is a smooth transition when the slide stop pin passes from the radius to the flat. THIS is the point where a round is being feed into the chamber. IF the barrel lug bumps the slide stop pin and the transition is not smooth, a jam going up the feed ramp is possible. The key is a smooth transition without bind.
Everyone does not need a rotary table to cut the barrel lugs properly, I use this method out of convenience. There are a few methods for cutting barrel lugs and they all work if done properly. Jack Weigand came out with a nifty little fixture and a video for fitting barrels, which is much less complicated then my set-up and will achieve the same results. Mike Curtis switched to Jack’s barrel fitting fixture. I never used the fixture yet but as with all of Jack’s tools, it’s clever, simple and will do a good job if used properly.
Hope this helps, Pete
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Metal Smith
The only thing I know for sure is what I can measure!
NRA Life Member
