difference between frame mount and slide mount

Zanemoseley made a comment in the thread at https://www.bullseyeforum.net/t10247-aimpoint-works-so-far#88493 

I love my Aimpoints but not a fan of frame mounts, too snappy for me.

I don't understand how frame mounts and slide mounts would "feel" different.  Can someone explain it?

Thanks.

Well since you referenced my post I'll give you my 2 cents. I'm not a ballistics expert but can tell you what I've experienced. 

If you look up recoil of different weapons you'll often see recoil energy and recoil velocity referenced. Combined they will determine how your firearm feels when being fired. The weight of the firearm affects recoil.

So I feel when you get a frame mount pistol the slide is relatively lightweight so the reciprocating mass moves quickly and contrubutes to a snappy feel that I'm not a fan of. I had a Les Baer frame mount that was my first 45, I don't think it did me any favors, the snappy recoil contributed to my flinch. When I went to a slide mount I immediately noticed the more pleasant recoil. Some might say a better barrel fitting on the Les Baer would have helped with recoil, how much I don't know.

I have now had 3 different slide mount pistols. One was a RRA, one a custom by Jon and one by KC. All have very pleasant recoil. I attribute it to the extra weight of the rib and 9000sc red dot all of which moves with the slide and smoothes it out. The recoil seems slower and more mild.

I know some smiths like David Sams swear by the frame mount pistols as they can be a bit more reliable. It does seem the majority of people prefer a slide mount but there are plenty of frame mount fans out there.

A frame mount gun recoils like a regular iron sight gun. Slide mount Guns are sluggish with all that weight

I shot slide mounts exclusively for nearly 2 decades. I'm now going to a frame mount so I can minimize the chance of another dot failure and I don't think the 9000 (pounds) type scopes are for me. the aimpoint micros are light enough that I don't think they chage the slide feel nearly as much as the larger optics. At least i didn't feel they did when I mounted the holosun and vortex on the slide. So why not improve thier longevity by minimizing the impact force they experience?  I am also liking the lower bore to optical axis that I get with my frame mount, but this is certainly not the case with all frame mounts.

Will accuracy suffer in the long run as the slide to frame Fit wears? Possibly, but I'll worry about that when I quit shooting 7's and 8's.

You may not get less force in the scope since the whole gun still takes the snap, in fact, the impulse may be sharper. You feel it in your hand, why wouldn't the scope experience that same force? The worst gun for scope damage is a spring air pellet rifle. Breaks scopes like mad.

Regards

There are many things that can be done to reduce the felt recoil in a frame mount gun.  Marry the ammo, recoil spring & mainspring are the start.

Frame mount recoil in a harder snap, but finishes faster. Slide mounts, even with lightweight scopes, recoil slower and takes longer to complete.

Frame mount recoil is a kick. Slide mount recoil is a push.

Frame mounts good. Slide mount bad (IMO).

Frame mounts are (probably) less likely to damage scopes. Slide mounts are (maybe) slightly more accurate (like 1/8" at 50 yds with a tight fitting gun).

I think Henderson is only shooter to break 2670 with a frame mount. Everyone else was running slide mount. I’ve talked to many many HM about this. We don’t like the frame mounts. It’s a feel thing.
Jon

The deciding factor for me was the ease of use with the slide mount.  I just grab the scope.  With frame mounts, you have to work around the mount, possibly even needing some version of charging handle, to operate the slide.

bruce martindale wrote:...
The worst gun for scope damage is a spring air pellet rifle. Breaks scopes like mad.

Regards

My ball gun with 230 ball ammo did a pretty good job on one of my very early scopes on a grip frame mount...

kc.crawford.7 wrote:There are many things that can be done to reduce the felt recoil in a frame mount gun.  Marry the ammo, recoil spring & mainspring are the start.

  I shoot a RO that Mallette put a frame mount on plus did other work on, but basically is stock. I shoot 185 swc cast with 3.8 WST and use a 11lb spring, never touched the MS. I have not ransomed it to check the load out yet, but will sandbag it until I find accuracy in that bullet. What MS weight would be in the ball park, and would I work towards a heavier RC spring to reduce felt recoil and be reliable? 
  I'm still having some trigger issues which are fundemental based with it, shoot the 22 much better. I'm thinking of a custom built 45 in a year or so but have to save some more moola. I need to make this gun work for me while I grind my teeth towards sharpshooter and expert, I figure in a year I'll have a BE smith start on a gun and a year later it would be done in time for my advancement. That's my plan, so I'd like this gun to work comfortably and accurately until then and do it affordably.

Chopper, that spring seems light for what you're running, unless the barrel lockup is super tight. I would image it would run with a 13# spring which should help your recoil. I would order 11-14# to try, I like variable springs but a lot use conventional springs.

chopper wrote:

kc.crawford.7 wrote:There are many things that can be done to reduce the felt recoil in a frame mount gun.  Marry the ammo, recoil spring & mainspring are the start.

  I shoot a RO that Mallette put a frame mount on plus did other work on, but basically is stock. I shoot 185 swc cast with 3.8 WST and use a 11lb spring, never touched the MS. 

The balance between MS and recoil spring can make a big difference on felt recoil.  Also for a wad gun you could (should?) be running a large radius firing pin stop, it also reduces felt recoil.  If you have too a heavy MS (23+lb) you will get a hard rap at the beginning of recoil.  Drop the MS down to 19 and that initial rap softens.  Then tune your recoil spring until it's just fails to lock back and go down 1 or 2lb.

KC just swapped my Red Buff frame mount for an integral cut slide mount so I could run an Aimpoint H1.  I was running a 19 lb mainspring with an 11lb recoil spring.  My loads for the frame mount were 3.8 of WST 185gr Zero LSWCHP.  With the new slide mount it is on the ragged edge of functioning so I increased my load to 4.1 of WST.  Now I've dropped my mainspring to 17lbs and the recoil to 10lb and went back to 3.8 of WST.  Now I think I might be able to go back to 11lb or maybe even 12lb and load to 3.8 WST.  I'll know in the next couple of days.  

- Dave
Why not try 3.9 or 4.0 of WST - I've never bench tested them.  No unknown variables.