What is the difference between 1911 and 1911A1 Thanks

Mainly the 1911A1 has an arched mainspring housing, a shorter trigger, and scallops on the frame behind the trigger. Also a different heat treatment for the slide. And the front and rear sights are a little different. Really not that much, all parts will interchange.

I believe this picture covers all the differences.

Attached Images

Differences between 1911 and 1911 A1.jpg (52.0 KB, 142 views)

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1911A1 modifications include: (US Govt. Model):
- Plastic molded grips vs wood checkered w/diamond
- Widening of the front sight
- Hammer modification (to help eliminate pinching the web of your hand)
- Arched mainspring housing
- Cutting "reliefs" in the frame behind the trigger guard
- Shortening of the trigger (and adding checkering).
- Lengthening of the grip safety spur.

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Are these changes specific to Colt, or are all pattern 1911A1's made this way? reason I ask is that my SA 1911A1 has all the aforementioned features, except it has the flat mainspring housing, and came that way, not been changed. My RIA is also an A1 and same deal, straight mainspring housing.

Unless it is a typo, the OP is asking for the difference between a 1911 and a 1911M1 (not A1).
I'm not familiar with the 1911M1, but all I can say is the 1911 would be the original and the 1911M1 is some sort of a wanna-be.

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Dean
SWCA #680 SWHF #446

The knowledge on this forum, never ceases to amaze me. Others just reading the thread learn as well (like me).

While not a fan of the platform, I do know a thing or two about it. One thing I would note is to avoid comparing other companies' 1911s, or 1911A1s, with original actual government models from any government contracting company or later developments from Colt. Commercial manufacturers don't necessarily copy the exact details unless they're literally making "clones" or "replicas". What SA or RIA call a 1911A1 is up to them, they're not bound by any requirements to match guns made for the government or even commercial versions made by Colt.

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The flat MSH seems to be the most popular and many 1911 makers are making it standard on all their pistols.
I don't like them and much prefer the arched. It annoys me to buy a new 1911 and the first thing I do is change the MSH to arched.

MSH is a personal choice, find flat or arched on match pistols. CCW about the same, depends on ones hands and how well one shoots either. Friend and I went shooting yesterday, he has an older “ Mil Spec” SA with fitted match barrel. Thing shoots as well as most match pistols, has 3 1/2 pound trigger and he only cleaned up the trigger, sear disconnector and hammer, amazing piece. He just got a 1911A-1 from CMP, did a clean up on internals and it is Very accurate. We shot quite a bit .The Turkish 1911’s are impressive, may look for one as lots of guys in gun club have them, shoot Very Well. Been “ around” 1911’s since late 60’s and on Army team after Vietnam. Carry LW customized Commander in 45. Love them.

I can detail strip my 1911/1911A1 pistols in about 2 to 3 minutes (much slower than I used to!) As I've gotten old, it takes me twice as long to put it back together.

Modern accessories are like Legos! Most will swap out and need no special fitment. One of my favorites was the Pachmayer MSH that was flat with a thin strip of soft rubber to absorb recoil. I'm not a fan of Beaver Tail grip safeties on Government and Commander sized guns, but I have "Discovered" the need on the Officer size models.

I'm not a fan of models that are without a bushing. John M Browning experimented with that idea and found it too expensive to get it to cycle reliably and adds unnecessary weight! If you think you need a barrel/bushing fit to your good old gun, buy a Colt Brand Match Finger Bushing (I think series 70 or 80)! Gunsmiths hate these, because they lose lots of "customizing" jobs to them! I used them with old used GI barrels and make guns shoot better than Brand New Colts of the 1980's!

I used to use Pachmayer grips but went back to checkered walnut. They seem to encourage consistent hand placement.

Ivan

If all the differences between the 1911 and 1911A1 are those listed above by JH1951, the only one that can't be changed around is the reliefs in the frame behind the trigger; the rest are just parts that should fit either series.

Doesn't the A1 also have a larger ejection port, or at least a reshaped one?

Colt discontinued using those collet "fingered" barrel bushings because many guns broke one or more of the fingers inside the slide when firing and more often than not that tied up the gun with a major malfunction.

They sounded like a good idea at first blush, but they had a fatal flaw.

I have a series 80 stainless steel Colt government model, and it came to me with the collet fingered bushing. I took it out and threw it away - replaced it with a standard bushing. I believe in the old adage that if it can happen, it will, and at the worst possible moment.

John

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I have broken one out of 6. Using Ball spec ammo the bushing fingers seem to last for thousands of rounds. I noticed breakage with +P ammo and of all things Target wadcutters! I have always expected the fingers to break at any time, but my primary 1911 has 24 years of service on that same finger bushing.

I would suggest you amend the above statement from "many guns" to some guns". I can't prove it but I think the barrel link length is the source of the breakage (and haven't decided if it needs to be one size longer or one size shorter). However the guns I built with the finger bushing, 5/6 never broke and only the one broke in the first few magazines of ammo and that is my primary 45, it is still going strong all these years later. Very cheap accuracy and can be returned to GI in about 45 seconds.

I also fell for the hype of full-length guide rods. Turns out, proper return spring poundage does away with the "snaking" the guide rod prevents. It adds about 2.5 ounces, and may complicate slide movement. J.M.Browning got it right without it!

I like my 1911's to be on the loose side. I never tried the thin mud test the Army Board used, but my 45'shave been in canoe accidental swimming's, and have functioned with mud and a different time sand all through the actions! Yes my 45's sound like a tambourine at a church meeting, but they go bang, first time, every time! With GI barrel and bushing I got 7 shots on a paper plate at 25 yards (or it didn't ship!). With a GI barrel, and a finger bushing, I got 2 to 3 inches at 25 yards. I never guaranteed accuracy, but did guarantee function!

Ivan

From what I've studied the lowered ejection port helps keep brass out of the shooters face, the flared part lessens the dinging of spent brass.

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