1911 Slide to Frame Fit

[9mmMike]

So, how important is a tight slide to frame fit in the function and reliability of a 1911 design pistol ? I don't see the real benefit when I study the mechanics, but I am no engineer for sure. Whats your thoughts ?

Read More

 

[billdeserthills]

While I seem to recall reading in Jerry Kuhnhausen's book that it is not needed, in reality I find that the most accurate 1911's (& 2011's) that I have shot do have a tighter fit.

 

[MountainBear]

A tight slide to frame fit contributes less to accuracy than a properly fit barrel. Barrel to slide and bushing, bushing to slide fit are all critical. I have found very little to know accuracy improvement with a full length guide rod. Often tight fits (like Kimber) lead to long break in periods where malfunctions may be experienced. I don't want a very sloppy slide to frame fit, however, there needs to be some room for reliabilities sake.

 

[asiparks]

A tight slide to frame fit contributes less to accuracy than a properly fit barrel. Barrel to slide and bushing, bushing to slide fit are all critical. I have found very little to know accuracy improvement with a full length guide rod. Often tight fits (like Kimber) lead to long break in periods where malfunctions may be experienced. I don't want a very sloppy slide to frame fit, however, there needs to be some room for reliabilities sake.

^ this^

Accuracy comes from the barrel locking consistently back up into the exact same position in relation to the sights. Barrel to bushing and barrel hood to slide is where it counts. The frame and slide can rattle like a coffee can of rusty nails, it will make no difference. If you are finding better accuracy on a 1911 with a tight slide frame fit, it's happy co incidence.
I see no difference at all between full length guide rods and GI set ups,

 

[Velzey]

The frame and slide can rattle like a coffee can of rusty nails, it will make no difference. If you are finding better accuracy on a 1911 with a tight slide frame fit, it's happy co incidence.

No that's just funny! And 100% wrong.....Have Nighthawk or Les built you a 1911 with sloppy frame to slide fit.....it wont shot for *%&^

 

[asiparks]

No that's just funny! And 100% wrong.....Have Nighthawk or Les built you a 1911 with sloppy frame to slide fit.....it wont shot for *%&^

righty then...care to explain using mechanical terms just how the slide to frame relationship has a bearing on where the bullets heading..... ?

you could argue that atrocious slide to frame fit might affect feeding, but it would have to be hilariously bad and only in tandem with a poorly fit barrel, bollocksed feed ramp geometry, useless extractor, knackered mags etc. If everything else is properly sorted, then frame and slide can rattle quite cheerfully

Baer , NH et al, have tight fit slides because that's the right thing to when you are charging a $2k+ gun.

I have a Brazilian Springfield Mil Spec that rattles just as described. It has a properly fitted Kart barrel and NM bushing and it's as accurate and reliable as any other 1911 I own.

 

[gunslinger1911]

In GENERAL tight is more problematic during break in periods, and more sensitive to debris creating a bind up...glocks are sloppy as heck and any media caught between the slide and frame will fall away as in the infamous "glock test"...personally I like a slide and frame fit to be "just right"

 

[gunslinger1911]

righty then...care to explain using mechanical terms just how the slide to frame relationship has a bearing on where the bullets heading..... ?

Isn't the barrel locking mechanism integrated into the slide???? Hmmmmm? Seems to me that barrel and frame relationship would be sloppy if the slide/frame fit is as well... just my .02

 

[jbett98]

Tight slide = 10%, tight barrel to bushing = 15%, quality trigger work performed = 15%, adjustable trigger 10%, the right grips for shooter 10%, adjustable sites 20%, quality ammo 10%.
And lastly a steady grip and good eyes. It all adds up to consistency in accuracy.

 

[MA Duce]

The other key item that most here seem to over look is the barrel link. When the barrel cams up into the locking lugs in the slide as it comes into battery, if the link itself is out of tolerance even with a good barrel bushing the barrel can "Float" a little up and down due to the play in the barrel link. In close range this might not be noticed, but over longer ranges it is a factor. When you pick up a 1911 grip the slide in the breech area and rock it side to side, there should be slight motion, but no more than about a 32nd of an inch. You can effect a remarkable difference in operational reliability and accuracy by replacing the bushing, the link, and using armorer's truing blocks to re-true the slide grooves. I won a very nice steak dinner and $50 dollars, ( when $50 meant something), by this simple overhaul on an issue weapon, ( a 1943 Singer) and match shooting against a Gold Cup in the hands of a fellow member of my pistol team.

 

[Velzey]

.010 slide side to side play equals .375 @ 50 yards. Plus all that extra space in there is just going to collect dirt and grime! Now that I think about it, what do you guys consider accurate for a 1911?

I have built many and while testing, if they do not put every shot within a 1" group at 25 yards, something is not fitted right. (I will note that is from a solid mounted Ransom rest)

 

[asiparks]

Isn't the barrel locking mechanism integrated into the slide???? Hmmmmm? Seems to me that barrel and frame relationship would be sloppy if the slide/frame fit is as well... just my .02

Yes, the barrel locking mechanism is integrated into the slide. As are the sights that you're aligning. That is why barrel to slide fit is critical, and slide to frame is not. The barrel is connected to the frame by the articulating barrel link through the slide stop pin. In theory the frame to slide fit could be so poor that the degree of movement could pull the barrel out of lock up, but that would have to go way beyond "coffee can" slop and somehow overcome the force of the recoil spring that's keeping the barrel locked up into the locking lugs. Which it can't. There's about 8 decades of very functional, accurate rattling service 1911 bearing testimony to this,.....

 

[RVTECH]

I have a lightly tuned 1991 A1 that will shoot into 2+ inches consistently (benchrest) with 4.0 grains of Bullseye and a 200 gr. SWC Laser Cast bullet at 25 yards.

 

[asiparks]

.010 slide side to side play equals .375 @ 50 yards. Plus all that extra space in there is just going to collect dirt and grime! Now that I think about it, what do you guys consider accurate for a 1911?

I have built many and while testing, if they do not put every shot within a 1" group at 25 yards, something is not fitted right. (I will note that is from a solid mounted Ransom rest)

In that case I would (sincerely) much like to shoot a 1911 you've built. Going by the advertised specs of some of my 1911's, nicely accurate would be a 5 shot 1 1/2" group at 25 yards, but I am not a bullseye shooter so it is well outside my abilities.... my math is rusty, but .01 side to side play in the slide/ frame fit will result in 3/8" deviation at 50yrds ? Really.
Curious what do you guys think at how many hundredths of an inch do you consider a 1911 "rattly"

 

[MountainBear]

Tight slide = 10%, tight barrel to bushing = 15%, quality trigger work performed = 15%, adjustable trigger 10%, the right grips for shooter 10%, adjustable sites 20%, quality ammo 10%.
And lastly a steady grip and good eyes. It all adds up to consistency in accuracy.

Have a reference for your assumptions, or are you just spitballing?

 

[asiparks]

Tight slide = 10%, tight barrel to bushing = 15%, quality trigger work performed = 15%, adjustable trigger 10%, the right grips for shooter 10%, adjustable sites 20%, quality ammo 10%.
And lastly a steady grip and good eyes. It all adds up to consistency in accuracy.

ahh...so if I'm understanding correctly, you're asserting that adjustable sights have a 33% greater bearing on accuracy than bushing fit ?


that's an interesting stance.

 

[spike1950]

If you were up to your rear in mud in the central highlands during the rainy season and all you had to wipe off your 1911 was your muddy sleeve or shirt-tail then you didn't want a tight slide. And if you needed your pumpkin thrower for anything over 20 feet, you were in deep gnuc-mom anyway!

 

[jbett98]

It was in an article I read last month about all the hype surrounding the 1911's and what the costs vs benefit you achieve by changing things to the pistol.
Of all the pistols I own, three being 1911's. my 1957 Colt National Match is by far the best. There is no rattle anywhere. That being said, it has a lightened slide, excellent adjustable trigger, Ellison target sites and even the magazine was tuned for this pistol. The recoil spring is around 12 lbs or less and shoots low power wad cutter ammo only.
My 1944 Remington Rand on the other hand sounds like something is loose and broken inside when shaken, and coupled with very small sites doesn't come close to the accuracy of the NM.

 

[MountainBear]

It was in an article I read last month about all the hype surrounding the 1911's and what the costs vs benefit you achieve by changing things to the pistol.
Of all the pistols I own, three being 1911's. my 1957 Colt National Match is by far the best. There is no rattle anywhere. That being said, it has a lightened slide, excellent adjustable trigger, Ellison target sites and even the magazine was tuned for this pistol. The recoil spring is around 12 lbs or less and shoots low power wad cutter ammo only.
My 1944 Remington Rand on the other hand sounds like something is loose and broken inside when shaken, and coupled with very small sites doesn't come close to the accuracy of the NM.

Be more interesting if we knew the origin of the article and the author.

I would say that a tight slide can be (but is not necessarily) indicative of good fit and finish elsewhere, such as the barrel lock-up (including the link) and barrel to bushing/bushing to slide fit. My S&W has a fairly loose slide to frame fit, but the barrel fit is excellent and the gun is accurate (sorry, never ransom rested it, but it works for my needs).

Here's a response that was posted by a 1911 guy on another forum when this question was asked there. I do not claim his answers as gospel, however they seemed to match my experiences as well:

Good vertical lockup and hood to slide fit, along with a good fit at
the muzzle between barrel and bushing...bushing and slide, and
the fit of the locking lugs in the slide's recesses to limit fore-and-aft
movement.

Vertical lock is obtained with the lower lug and the slidestop pin,
not the link. Installing a long link is counterproductive and can do
damage over the course of 4-5,000 rounds.

Hood to slide fit limits barrel rotation, and should be fairly close,
but not so close as to cause functioning issues. I like about .002
on each side for accuracy tweaks, and looser for a carry gun. Some
match tuners will get this clearance tighter than .002 inch.

The barrel bushing is normally fit as loose as .005 inch or even more on
entry level production guns. Match grade pistols get this down to a
half thousandth, but about 001 to .0015 is a good working number
for good accuracy without compromising function. I normally set mine
at .002-.003 for reliablity.

Bushing to slide can be anywhere from slightly snug to requiring a wrench to turn it. I like snug and being able to strip the gun without having to carry a special tool along.

Slide to frame fit is responsible for about 5% of the total potential...or less.
I like .002-.003 inch clearance here for game pistols and range beaters.
.004-.005 is fine for a carry gun, as long as vertical play is held to a minimum...preferably none, bit .001-.002 is okay too. Again, reliability
is paramount. Snce I'm not a game player or bullseye competitor, I
take only a passing interest in a high degree of accuracy in a 1911.
If the pistol will shoot into 5 inches at 25 yards, it will do for what I
need it for. I'm almost anal about reliability, though.

The one thing to keep in mind is that accuracy means having to make things
tight. Tight means that the gun won't tolerate dirt or neglect as well as
a looser, "Ordnance Spec" pistol will, all else being equal. I've seen some
amazingly accurate National Match pistols that required cleaning as often
as every 50-75 rounds. It was an accepted consequence of those one
ragged hole 50 yard groups. Would I carry a pistol like that? Not if I
had a choice.

Cheers!
Tuner

 

[jbett98]

Mountainbear. I would agree with the above article. The whole point I was making was that there is cost / benefit ratio to improving the accuracy to a 1911 slide. John Browning made his
Hi-power with internal rails and they are very accurate pistols without all the effort that 1911's owners go through.