Frame Mount vs. Slide Mount for Optic

Newby shooter here.  I've been lurking for a while and the information on here has been great.  You guys have taught me so much already, so thank you!!

I've been shooting strictly a customized Ruger MkIV .22 for a few months to try to develop good fundamentals and am starting to think about getting a .45 wad gun.  Is there a general consensus on frame mount vs. slide mount or is it dependent on the particular pistol + optic.  I'm currently shooting an Ultradot, Matchdot II that I went with because it gave me the ability to try a bunch of range of MOA dots and a couple reticles.

Most of the guys on the AMU team liked the Slide mount better than Frame. At one time Henderson was giving a demonstration to someone that asked this question. With a simple iron sight 1911 (slide was open and EIC in place) Discharge was indicated by him saying Bang. Slide mount raised in typical  recoil up about a foot and slightly left (right hand shooter) Then Frame mount, a bit exaggerated I'm sure but gun recoiled up about 3 feet and about a 2 feet left and arm waved as a flag in a wind storm.
 I have been using slide mount on my 1911 builds and prefer it.
 Also if you think about it the barrel never contacts the frame. It's only frame contact when locked-up and ready to fire is the slide stop pin. Therefore a barrel properly fitted into the slide and optic fitted to the slide will give best results.
 Some time ago a friend decided to test his slide mounted 1911 in the gun clubs ransom rest. He was surprised to see it didn't do as good as he expected! I told him to try it again but after every shot check the red dot and adjust the rest so the dot was in the centered of the target. Gun shot great! Ransom Rest repeated but holding the frame. Since you as the shooter use the dot to repeat location it makes sense to use the slide!

There is no consensus. Slide mounts are more common, but both are readily available from all the bullseye gunsmiths. The primary difference is in the feel of recoil. Great scores have been shot with both. If possible borrow guns with both and see how they feel.

A slide mount has a lot more moving mass. Some say this lessens the feel of recoil because it becomes more of a slow, gently shove. Others say the increased mass takes longer to recoil so it is harder to get back on target.

A frame mount has a lighter slide. Some say this makes it easier to get back on target because the gun recoils faster. Others say the recoil is uncomfortable because it is more of a sharp kick.

There are other less importance differences.

It is much easier to rack a slide mount gun because the scope makes a great handle and the recoil spring has to be lighter. Frame mounts get in the way of your fingers and need a stronger recoil spring. Many slide frame mounts add a slide racker handle to the rear sight dovetail.

I don't see much difference in ease of cleaning. You can't soak the slide in a slide mount and you can't soak the frame in a frame mount. Same difference. The frame mount does get in the way of part of the rails, but nothing a q-tip can't solve.

Some argue there is an accuracy difference, but IMO the bottom lug is on the frame and the bushing and top lugs are on the slide. Either way slide to frame fit is a factor and modern metallurgy & gunsmithing has pretty much eliminated slide loosening.

Oh yeah, one other difference I forgot initially is that there is no good place on the frame to attach. The top of the slide has pretty thick metal to attach a rail. The sides of the frame are pretty thin, so mounts like the Weigand Frame Mount use a lot of screws to make sure it remains in place. I've had a Weigand on my primary bullseye gun for 50k+ and no problems.

There are 3 things at play. Recoil impulse, sight acquisition and ease of use. Slide mounted recoil impulse is slower. Not better or worse, just different. I cannot say gun recoils better/less with slide mounted, just slow. All things equal sight acquisitionis faster on frame mounted since the dot does not move. Hence mostly frame mounted are used in competjtive action shooting. This is obviously not critical in billseye shooting. One win on the slide mounted is the ease of use. Much easier to clean, rack, etc than the frame mounted. Is it a huge deal? Not really, a great gun with frame mount is much better than mediocre with slide mount.

Another question is reliability of mount. Slide mount wins here. Frame mount needs to be properly done so as not to mess up the frame. If unscrewed to clean or re-torque it is easy to mess up the threading.

∆ +1 what Steve said.

Thanks very much guys. Appreciate it.

I like Frame mount for all but light recoil Rim Fire.

SteveT wrote: Many slide mounts add a slide racker handle to the rear sight dovetail.

I'm sure Steve meant - "frame" mount here.

It is rather another complication with frame mounted optics.  Slide racker can only stick out to the right.  Otherwise it would interfere with disassembling gun for cleaning.  Such would work well for left handed shooter.  However for right handed shooter it means complications, - switching hands or rotating gun counter clockwise 90 degrees.  Nothing that can't be overcome, just inconvenience.

AP

Screws require 3 threads so as to provide the strength of the size screw used. Location on the Frame where Frame mount is installed is thin. AMU did build some good Frame mount pistols but a piece of steel was welded to the Frame to provide the needed material thickness. Properly done it adds considerable cost to the build! No rail is wear resistant, it will wear and does it will requires tightening from time to time depending on how much the gun is shot. I have found that the Slide mount is less dependent on slide tightness. In addition a loose frame/slide functions better.
 Accuracy, a well done Frame mount or Slide mount is as accurate as the other. It depends on the shooter liking the recoil as a jab or a push. I like the push!
 Adam used Slide mounted 1911 for his Bullseye gun yet used the AMU 1911 frame mount in 9mm for Bianchi type action shooting. Adam did blame the Tendinitis he got from shooting the Frame mounted 1911 when started with the AMU. I'm not going into why the AMU changed to Slide mount but it was well liked by the shooters .    However keep in mind the AMU shoots about a 2700 everyday for 5 days a week so Tendinitis should not be an issue to the average shooter.
 I would suggest that the OP ask a few shooters that own accurate 1911s in Slide and Frame mount to allow him to shoot a few rounds with each style.

I am right handed and have frame mounted optics in both 1911 and 2011, which are right mounted for slide racker with option to mount them left. I much prefer right mounted racker. Sounds strange? Well that 90 degree rotation comes very natural to me and gun levers much better for me that way
 So if you do find a gun with right side racker it does not mean it is a leftie.

I like both, each has advantages. If you like light, snappy recoil (think .22, 9mm) frame mount is better choice. They are inconvenient to clean/ disassemble unless you have a bushingless bull barrel. If you like a slow, controlled “chug” recoil, like .38 special or a longslide, slide mount is for you. Dot recovery is a tiny bit more challenging with slide mount also. You really just have to see what you like best. I enjoy both and could shoot well with either, would just have to pick one and put in the time to get used to it.

Frame mounts tend to be more reliable, since you're not drastically altering the weight of the slide beyond it's designed weight. You can use lighter loads with a frame mount and maintain reliability. Depending on the frame you use, dust cover thickness isn't really a factor. For example, my frame mount gun is built on an STI Rangemaster frame that's got plenty of meat for screws.
The advantages of slide mounts are that they're more tolerant of looser frame to slide fit and they're easier to slap a scope mount on.

PhotoEscape wrote:

SteveT wrote: Many slide mounts add a slide racker handle to the rear sight dovetail.

I'm sure Steve meant - "frame" mount here.

It is rather another complication with frame mounted optics.  Slide racker can only stick out to the right.  Otherwise it would interfere with disassembling gun for cleaning.  Such would work well for left handed shooter.  However for right handed shooter it means complications, - switching hands or rotating gun counter clockwise 90 degrees.  Nothing that can't be overcome, just inconvenience.

AP

My Kimber 38 super has a frame mount with a slide racker in the rear sight dovetail.
My Rock River has a slide mount that incorporates a pair of ears to grab in case grabbing the scope offends you.
The racker on the Kimber is only a slight snuggixh fit & locked by a set screw so it's easy to remove and can be on either side.