New Frame Mount Coming Out

New Eulette Precision frame mount coming out soon for 30mm Optics. 5 screws attach to left side of the frame. Integral plunger tube. Grip needs trimmed to clear the mount. Working on a drill pattern template so you can easily install it yourself.
Jon

At the risk of starting an argument that might have no end...what are the advantages or disadvantages of frame mount vs slide mount?

I can’t wait to see this!

TexasShooter wrote:At the risk of starting an argument that might have no end...what are the advantages or disadvantages of frame mount vs slide mount?

Personal preference. They both recoil quite differently. So it boils down to what ‘feel’ you prefer. No difference in accuracy unless your frame to slide fit is loose on the frame mount. Lighter charges can be run on frame mounts; typically.
Jon

So is it similar to the old "Red Buff" mount that also had the integral plunger tube?  The Red Buff was nice, but the angle of the rings was distracting. 

Looks like the rings are integral with the mount.   One inch or 30 mm?  Will you be doing version with weaver / picatinny rail rather than rings?

FWIW, I really like frame mounts.

CR

how about an Aimpoint (or Holosun/Primary Arms) mount.

This mount has vertically split rings, so no Red Buff goofiness lol. Aimpoint 9000 just clears the slide . I guess I need to look into adding Weaver and Aimpoint Micro options.
Jon

Anyone have experience with this mount? 

https://www.doublealpha.biz/us/daa-aimpoint-micro-sight-mount

rich.tullo wrote:Anyone have experience with this mount? 

https://www.doublealpha.biz/us/daa-aimpoint-micro-sight-mount

Three mounting holes go into the dust cover on the receiver where the frame is extremely thin. One of the three screws hits thicker steel. One hard impact with this type of mount and you risk damaging the frame. That’s why Dave Sams uses steel plate silver soldered to the frame for his mounts that mount in this area on the frame. I should add that the picture is one of the more modern 1911 frames with a thicker dust cover, our typical Bullseye Pistol do not have that thick of a dust cover.
Jon

TexasShooter wrote:At the risk of starting an argument that might have no end...what are the advantages or disadvantages of frame mount vs slide mount?

Slide Mount

• Requires / Allows a lighter recoil spring so the slide is easier to manually rack and it has the scope as a nice handle, but it may not lock up as solidly due to lower spring force and higher mass
  
• The slide cycles slower so the time to get back on target is slower and the sights are (usually) disturbed more
  
• Cleaning the frame is easier because there's nothing in the way and you can dunk it in cleaner / ultrasonic if you want
  
• Cleaning the slide is slightly more of a hassle because you don't want to get chemicals in/on the scope - Overall cleaning is easier with a slide mount
  
• The slide has quite a bit of metal to use to attach the mount and it's surface to surface contact so the mount is very secure and reliable.
  
• Slide mounts are MUCH more popular on the firing line
  

Frame mount 

• Requires / Allows a heavier recoil spring so the slide is harder to manually rack, but it locks up more solidly
  
• The slide cycles faster so time to get back on target is faster, usually the sights are disturbed less, a weak grip won't see this advantage
  
• Cleaning the frame is more of a hassle since the damn mount gets in the way and you can't dunk the frame in cleaner / ultrasonic
  
• Cleaning the slide is easier because you can dunk it in cleaner / ultrasonic if you want 
  
• There is no good way to attach a mount to a 1911 frame, all the metal surfaces are thin so frame mounts are big and use a lot of screws, plus it sticks up in the air, so there is a good lever arm that can bend or break - All the frame mounts I've seen are reliable, but mechanically it is not as good as a slide mount.
  

The recoil energy is the same, regardless of the mount type. The main difference is how the recoil feels. With a frame mount it is a higher impulse, but dissipates quickly so it feels more like sharp kick. With a slide mount, it is spread over a longer time, so it is a lower peak but takes longer to complete so it feels more like a shove or push. Note that we are probably talking about 1/20th or 1/10th of a second difference, but it is noticeable. 

IMO If the shooter has a strong arm, wrist and grip, a frame mount gun produces less recoil movement and recovery is faster. If the shooter is not as rigid, there is not much advantage to a frame mount, but ultimately it comes down to personal preference. 

If anyone out there can do it, I'd love to see a 1911 with a dovetail on the dust cover so we could use a mount like the Hammerli 208. I'd be first in line.

There are many makers of 1911s who have Picatinny attachments on the dust cover.  Why have those not been used for optics mounts in bullseye?

Just a curious question:  Since the dust cover is so thin, could flat head screws be used from inside the cover and thread the mount?  Maybe the countersink could even be continued into the mount.  The work would need to be pretty precise, but we do have that level of machining available.

In the single side frame mount configuration, the 3 screws in front of the slide stop pin may or may not be sturdy enough.  But I have a few of the old Springfield Armory Aimpoint Comp scope mounts (they have integral rings) that mount in front of the slide stop pin.  They have 3 screws on either side (its a "saddle type mount") and like Jon said, on each side, two are in the dust cover and one is in thicker metal.  They have held up perfectly for about 15 years.  I have them on my "lead only" guns so I have a wider range of loads I can use with just a recoil spring change.  

As far as SteveT's  comments, most are ok but I'll take exception to the recoil spring comments.  The recoil spring requirement is more of a function of the lock up, slide weight and load.  I can run very light recoil springs and much softer loads with a frame mount than with a slide mount.  With the extra mass on the slide, there is a higher minimum impulse required to get the action to consistency unlock and cycle compared to just the slide (with a frame mount).  Definitely agree with how it "feels".  Keefer eventually got to the point of lead loads and slide mounts for the "minimum" recoil "feel".  But some people like the "clunk" of a slide mount gun going back into battery for the recovery process.  I kinda favor the slide mount for jacketed loads that have a snappier or quicker recoil impulse.  As for durability, see comment above.  

CR

Ed Hall wrote:Just a curious question:  Since the dust cover is so thin, could flat head screws be used from inside the cover and thread the mount?  Maybe the countersink could even be continued into the mount.  The work would need to be pretty precise, but we do have that level of machining available.

The slide barely clears almost flush screws on the interior of the dust cover. Sams and Keefer machined a flat on the slide to clear the screw tips. So I say no to that Ed.
Jon

[quote="Jon Eulette"][quote="Ed Hall"]Just a curious question:  Since the dust cover is so thin, could flat head screws be used from inside the cover and thread the mount?  Maybe the countersink could even be continued into the mount.  The work would need to be pretty precise, but we do have that level of machining available.[/quote]

The slide barely clears almost flush screws on the interior of the dust cover. Sams and Keefer machined a flat on the slide to clear the screw tips. So I say no to that Ed.
Jon[/quote]
Its also bad mechanical design practice since the c'sink in the "forward" part needs to be deeper to make sure you are truly pulling the parts together and not bottoming out on that forward c'sink.  Yes, I've used it but I wasn't proud of myself.  Not to belabor it but there are two different c'sink angles (82 and 100 deg) so maybe the larger/shallower style could work. Its head height (requiring the dust cover thickness to be slightly thicker) is .060 in. for a #6.

Same height for an undercut head at 82°. I was a little surprised to find them in alloy steel.

You're also going to need a back countersink cutter. And maybe some mod's to get it to clear.

Better might be threaded bushings like the grips use. And they could also key the base in place.

Ed Hall wrote:Just a curious question:  Since the dust cover is so thin, could flat head screws be used from inside the cover and thread the mount?  Maybe the countersink could even be continued into the mount.  The work would need to be pretty precise, but we do have that level of machining available.

These are all questions that the USPSA world solved almost 30 years ago...and we were shooting 175-180pf loads, not mouse fart bullseye loads. There have been a few ways to address this:
1. Lots of thin screws...like 5 on a side. Weigand, Wilson/Clark, and several others did or continue to do this.
2. Braze/solder on pads to the dustcover strengthen the mounting point. Springfield Armory and World Class Pistols, inc (George Huening) did this, and now David Sams too.
3. Unthreaded locating pins along with screws and/or braze/solder on pads. WCPi did this...(maybe David Sams too?)
4. Mounting to the more substantial rear half of the frame. Red Buff did this, and now Eulette Precision will too.
5. Using frames with longer wider/thicker dustcovers. Back in the day, McCormick/Tripp/STI/SV widebody frames started incorporating wider and thicker dustcovers to provide stronger mounting points for scope mounts, as well as greater non-reciprocating inertial mass to counteract recoil.
6. Some combination of the above. (Which is what I went with.)

As to SteveT's assertion that frame mounts stick "up in the air," here's a pic of my STI Rangemaster with a WCPi frame mount, right next to my KC's Custom with a typical slide mount...it might be a little tough to see because of the angle, but note the relative heights of the bottom of the scope tubes.

mpolans wrote:
As to SteveT's assertion that frame mounts stick "up in the air," here's a pic of my STI Rangemaster with a WCPi frame mount, right next to my KC's Custom with a typical slide mount...it might be a little tough to see because of the angle, but note the relative heights of the bottom of the scope tubes.

I meant when the slide was off the gun if it is hit or dropped it is MUCH more likely to bend than a rail on top of the slide.

Most frame mounts are higher than slide mounts, but not by enough to make a difference. Frame mounts that rotate the scopes can get closer to the barrel line, but again, not enough to matter.

Hello,

The lower gun in the photo - what is the mount made of? Looks like Carbon Fiber texture in the photo? Where can you buy it?

Thank you

Gustavo1957 wrote:Hello,

The lower gun in the photo - what is the mount made of? Looks like Carbon Fiber texture in the photo? Where can you buy it?

Thank you

It's a WCPi carbon fiber over aluminum honeycomb mount. They made two versions; mine is one that was geared toward Tasco ProPoints and another version geared toward Aimpoints. It's out of production, so they're kind of hard to find.

David Sams' mount looks almost identical, except his is made out of aluminum.

Thank you for the info!

Would the integral plunger tube be CMP service pistol legal if one removed the mount?

You can run a plunger tube without staking into the frame if you have a grip that will hold it in place; been there done that.
Jon

Jon Eulette wrote:You can run a plunger tube without staking into the frame if you have a grip that will hold it in place; been there done that.
Jon

Something Remington took advantage of on early R1’s! Lol