Converting 1911 to 45 Super

[cityfarmer]

I've decided to convert one of my 45 ACP caliber 1911 pistol to 45 Super. I don't really need a 45 Super as I already have a Ruger Blackhawk in 45 Colt which I load as "hot" as 290gr SWC to 1,150 fps. for hunting hogs/deer and occasional plinking. In reality a 45 caliber load of 250gr SWC @ 1,100 fps is enough for practically anything in the lower 48 states except large brown bears and moose. I guess I'm doing this project because I'm not working on anything else and just because I never had a 45 Super before.

I chose to convert a 1911 pistol because I have 30+ years of experience with this pistol. I used to shoot a lot of 45 ACP rounds through various 1911 pistols...about 15k rounds per year for about 10 years so the pistol feels very natural to me. I also have about 4 years of experience with 1911 pistols in 10mm and learned some lessons on shooting high pressure loads through 1911 pistols.

My goal is to safely shoot 230gr bullets at 1,200 fps with good accuracy out to 50 yards. I'm going to "cheat" a little in reaching my goal by using 6" barrel instead of standard 5". Based on my 10mm high pressure load experience of past, that extra inch should give me about 60 fps extra velocity.

To start I ordered a new 6" Jarvis drop in barrel and fitted barrel bushing from my friend. It's an old stock but never fitted or used...and I got it for good price. For frame and slide I have a new Colt series 70 Government, old Colt Combat Elite and a Kimber Target that I can use. When the barrel arrives I'll try it on each pistol and choose the one with the best (most) barrel lug to slide slot fit/engagement for maximum durability.

My list of other changes for the conversion are as follows:

Recoil spring - 24 lb.
Hammer spring - 30 lb.
Extra power firing pin spring
Extra power magazine spring (will be using Colt factory 7 round mags)
Small radius firing pin stop
Forged slide stop
Titanium firing pin (not necessary but it doesn't hurt)
Full length recoil guide rod (not needed but give extra weight to pistol)
Steel MSH with magazine guide (not needed but give extra weight to pistol)
Pachmyr Combat grip (has steel panel in the grip to protect hand in case of case rupture)

Finally I'll have to order 500 45 Super brass from Starline...plus some appropriate bullets.

I'll update this post as I proceed with the conversion.

BTW. Sometime in future I plan on converting my Glock 21SF to shoot 45 Super too but that will be much simpler than converting 1911.

[cityfarmer]

I finally got the pistol assembled enough to test fire 100 rounds of standard and +P ammo...no 45 Super yet.
I ended up using the Kimber as it had the best lug engagement and it's the pistol I shoot the least for past few years. It also has the low mounted Bomar adjustable sight which I thought could be useful to sight in the loads. I tested the weight of springs I had in my spare parts bin and found a 25 lb. recoil spring and 28 lb. hammer spring so that's what I used. For magazine I used a new CMC Power Mag with extra power spring (which made it 7 round mag). Everything went together pretty easily except the barrel bushing. The Jarvis "match" bushing OD was too large to fit on the Kimber slide so I had to fit the bushing to the slide. It took about an hour but there were no surprises and only minimal amount of material had to be removed to fit. I left it pretty tight so bushing wrench is need to remove it.

First I fired 25 rounds of Winchester 230gr FMJ ammo. According to the chronograph the average velocity was 840 fps. There were no malfunction of any kind and empty brass all landed about 3-4 feet at 3 o' clock position. Last 7 rounds were fired on a steel plate from 20 yards and all 7 rounds hit the 8" plate relatively centered.
Next I fired 25 rounds of my 230 gr XTP handload. According to the chronograph the average velocity was 870 fps. There were no malfunction of any kind and empty brass all landed about 4-5 feet at 4 o' clock position. Last 10 rounds were fired on a steel plate from 20 yards and all 10 rounds hit the 8" plate relatively centered but gave much tighter group than the 230gr FMJ ammo.
Finally I fired 50 round of Hornady 230 gr XTP +P factory rounds. According to the chronograph the average velocity was 920 fps. There were no malfunction of any kind and empty brass all landed about 6-7 feet at 4 o' clock position. There was increase in felt recoil but was not what I would call excessive or uncomfortable. The Pachmyr rubber grip felt good with this load. I fired 14 rounds at a 18" steel plate from about 75 yards and it was hitting the plate on most shots. I fired 0 rounds on a steel plate from 20 yards and all 10 rounds hit the 8" plate but about 3" higher than other 2 loads. I was surprised by the size of the group with this +P load...all 10 rounds were inside 3" inches with best 8 rounds within 1 1/2". I adjusted the rear sight and got it sighted in with this +P load.

I think the extra 1" length of Jarvis barrel is giving some extra velocity but I'm not sure how much. In future I'm going to fire some loads with both the original 5" barrel and this 6" barrel to see the differences.

In next few weeks I'll load some 45 Super loads and see what this pistol can do.

[David]

That will be interesting to see.

[Mac66]

I've put heavy recoil/hammer springs in 2 of my 4 45 acps with the intent of using them for 45 super. I haven't ordered any 45 super brass yet as I am working on several other gun projects and saving cash for incidentals concerning our house building. Kind of on a moratorium from spending until at least Sept. None the less, I'll be loading up some 45+P loads. I noticed that regular ball ammo wouldn't cycle the slides reliably due to the increased 22 lb and 24 lb springs I put in. Perhaps I need heavier mag springs as well.

[cityfarmer]

I'm surprised your standard pressure ball ammo didn't cycle the slide.
I'm running 25 lb. recoil and 28 lb. hammer spring with small radius firing pin stop and extra power magazine spring. While the brass doesn't eject very far it's been totally reliable with factory ball ammo and my standard pressure reloads. I don't think extra power magazine spring will help in your case as the purpose for the extra power spring is to reliably push the cartridge up into the feeding position in the magazine in time for the fast moving slide to pick it up as it goes back into battery. Extra power magazine spring may slow down your slide even more as it will exert more pressure on the bottom of your slide and increase the friction between the slide and the frame.
Have you chronographed the load to see the real velocity of that load...maybe it's slower than you think?

BTW. are you using the factory barrel or aftermarket barrel with better case support?