Frame vs slide mounted scope

Seems like almost all of the 1911s I see at a BE match are slide mounted (including mine). However, this seems to be counter intuitive to me because there is more mass moving back and forth with shot so possibly more wear on the gun? 

Possibly more wear on the scope and mount? 

Mounting the scope at the rear of the slide has the most comfortable balance for me. 

Is the balance different with a frame mounted scope? 

-Trevor

Balance is balance. In other words, where you put your scope is going to affect the balance. A frame mounted optic, the slide comes back really fast, and has more felt  recoil than a slide mounted optic. In my opinion, shooting a frame mount, requires using a fast twist barrel, and Powderpuff loads to come close to the same recoil as a slide mounted optic. I shoot lead bullets and hand loads. I don’t feel the need for shooting the warmer most accurate load approach. When shooting a 16 twist barrel, I will load 3.7 grains of bull’s-eye minimum for the long line and down to 3.4 grains for the short line. When I use my 13 twist frame mount, I use 3.3 grains of Bullseye maximum for the long line and 3.0 grains for the short line. My slide mounted optic pistols have less felt recoil than my frame mount. My frame mount requires two hands to unlock slide out of battery. It locks up tight!
Slide mounted is my preference even though I’ve been shooting my frame mount for last couple of years.
Wear and tear are part of the game. Scopes get abused on the slides and recoil is harsher with a frame mount. If gun is built correctly they stay tight for many years.
One of my customers had 10k rds through his ball gun I built him. Dave Sams tested it in the HEG rest and it shot 1” group. Still really tight pistol.
Jon

Jon, what recoil spring rates do you use with the slide mounted scope and the 3.7/3.4 Bullseye loads?

10# recoil spring. Barrel lock up is tight!
Jon

My perception of recoil is different than Jon's (and most BE shooters). To me, frame mount recoil is a short sharp kick that springs right back to the target faster while a slide mount is a long slow shove which disturbs the sights more, but it really is a personal thing. I don't shoot puffball loads.

A slide mount makes racking the slide much easier. 

Frame mounts hold the scope slightly higher above the barrel. I don't see a difference in my sight adjustment so I don't think it is significant. I recall seeing a Double Alpha mount that held an Aimpoint sideways so the tube was almost touching the slide, closer than you could get with a slide mount rib, but that isn't the norm.

The best option is to try each and see what you prefer, but you can learn to shoot well with either so if you don't have a strong preference for a frame mount, go with a slide mount.

I agree with SteveT, Recoil is softer with slide mount. AMU started with Frame mount on their 1911s than changed to Slide mount. Might be a few shooters there that want slide mount but a per a few years ago slide mount was being used by most. I use slide mount on my 1911s. Being I use the 185gr. JHP bullets I reload with powder amount that will give me the smallest group size. Loads are a little snappy, I assume increased velocity increases spin rate to best for bullet used. Lowering the recoil to more of a push rather than a snap by use of Slide mount, works for me.

Slide or frame mounts are personal preferences. And neither is right or wrong.
When I first started shooting Bullseye there were custom made slide mounts and grip mounts, frame mounts were not the scene yet or I hadn't heard of them. 
My first red dot/scope was on a grip mount and it was not the best idea in the world. It constantly changed point of impact and I had to have the frame drilled and taped to anchor it and the accuracy did improve.
Then someone decided to make a video at the club to promote shooting Bullseye and the video showed the scope twisting in the mount when pistol was fired mounted in a ransom rest while viewed in slow motion.

I found a good slide mount and had the slide drilled and taped and never looked back.

My .38spl wad gun has a frame mount so I didn't have to deal with function problems and leading from warm loads. It is almost like shooting a .32.

I think Jon is right in that to take advantage of the 1-13 twist barrel a frame mount with light bullets and light powder charges would be the best way to take advantage of the 1-13 twist barrel.
I have a 1-13 twist that Jon put in my wad gun and have tried from 160gr to 200gr cast bullets that I cast, each was hand weighted and sized for consistency and accuracy. I couldn't get the 160's powder charge light enough to take advantage of them and still function reliably. 175gr and up did show great promise.

Jon Eulette wrote:Balance is balance. In other words, where you put your scope is going to affect the balance. A frame mounted optic, the slide comes back really fast, and has more felt  recoil than a slide mounted optic. In my opinion, shooting a frame mount, requires using a fast twist barrel, and Powderpuff loads to come close to the same recoil as a slide mounted optic. I shoot lead bullets and hand loads. I don’t feel the need for shooting the warmer most accurate load approach. When shooting a 16 twist barrel, I will load 3.7 grains of bull’s-eye minimum for the long line and down to 3.4 grains for the short line. When I use my 13 twist frame mount, I use 3.3 grains of Bullseye maximum for the long line and 3.0 grains for the short line. My slide mounted optic pistols have less felt recoil than my frame mount. My frame mount requires two hands to unlock slide out of battery. It locks up tight!
Slide mounted is my preference even though I’ve been shooting my frame mount for last couple of years.
Wear and tear are part of the game. Scopes get abused on the slides and recoil is harsher with a frame mount. If gun is built correctly they stay tight for many years.
One of my customers had 10k rds through his ball gun I built him. Dave Sams tested it in the HEG rest and it shot 1” group. Still really tight pistol.
Jon

Holy smokes…you can get your gun to cycle with 3.0gr of Bullseye!!! What weight bullet? 

I shot my 1911 last year with only irons and a 12.5 lb spring and had to use 4.0gr of Bullseye to cycle the gun.

Slide mount feels so much better to me in regards to recoil impulse and my ability to recover. Frame mount felt much snappier with same loads. The points lost going from 22 to 45 is mostly due to recoil anticipation and shot recovery time. I also like a pistol at about 3.25# with a 9000SC, hold as much weight as you can comfortably shoot, heavier slower slide that still functions properly is what I've shot best with.

hengehold wrote:

Jon Eulette wrote:Balance is balance. In other words, where you put your scope is going to affect the balance. A frame mounted optic, the slide comes back really fast, and has more felt  recoil than a slide mounted optic. In my opinion, shooting a frame mount, requires using a fast twist barrel, and Powderpuff loads to come close to the same recoil as a slide mounted optic. I shoot lead bullets and hand loads. I don’t feel the need for shooting the warmer most accurate load approach. When shooting a 16 twist barrel, I will load 3.7 grains of bull’s-eye minimum for the long line and down to 3.4 grains for the short line. When I use my 13 twist frame mount, I use 3.3 grains of Bullseye maximum for the long line and 3.0 grains for the short line. My slide mounted optic pistols have less felt recoil than my frame mount. My frame mount requires two hands to unlock slide out of battery. It locks up tight!
Slide mounted is my preference even though I’ve been shooting my frame mount for last couple of years.
Wear and tear are part of the game. Scopes get abused on the slides and recoil is harsher with a frame mount. If gun is built correctly they stay tight for many years.
One of my customers had 10k rds through his ball gun I built him. Dave Sams tested it in the HEG rest and it shot 1” group. Still really tight pistol.
Jon

Holy smokes…you can get your gun to cycle with 3.0gr of Bullseye!!! What weight bullet? 

I shot my 1911 last year with only irons and a 12.5 lb spring and had to use 4.0gr of Bullseye to cycle the gun.

When I build 1911’s I fit barrel to cycle 4.0 BE 185/200 for test fire load using 10# recoil spring; wad or ball gun. Pistol will run 3.6-3.7 after couple hundred rds. If customer is planning on shooting lighter loads I fit barrel accordingly.
My frame mount is pretty dang tight. It will run 2.8 BE in summer months. I’ve primarily used 180 Brazos and 200 Zeros in this pistol. Testing showed that with 3.0 BE 180 Brazos velocity was 622 fps. It also held X ring at 50 yds with really good lead bullets!

My ball gun builds will usually run 3.8 BE 185 jhp. I recommend this load for eic matches. Shoots on call.

Jon

Are the increasingly popular rmr / rugged micro reflex sights worthwhile for bullseye?  It looks like would be simple to slip in adapter plate in the rear sight cut and attach a light weight rmr sight to a starter/ball gun with little or no change in ammo or springs.  The compact ones they are selling for concealed carry guns would have an even lighter footprint.

The reflex dots are ok for bullseye with a couple of caveats.  They can be a bear to recover from recoil and reaquire the dot.  That will improve as your recoil management gets better.  They are also “open emitter” which can be problematic in dust or rain.  I use them on my 52 and my 745 S&W.  They work well and are accurate. 

I read somewhere that you should 'calibrate' your recoil spring to
the load you are shooting to help with dot recovery-are there any links here on that subject?

Jon Eulette wrote:

hengehold wrote:

Jon Eulette wrote:Balance is balance. In other words, where you put your scope is going to affect the balance. A frame mounted optic, the slide comes back really fast, and has more felt  recoil than a slide mounted optic. In my opinion, shooting a frame mount, requires using a fast twist barrel, and Powderpuff loads to come close to the same recoil as a slide mounted optic. I shoot lead bullets and hand loads. I don’t feel the need for shooting the warmer most accurate load approach. When shooting a 16 twist barrel, I will load 3.7 grains of bull’s-eye minimum for the long line and down to 3.4 grains for the short line. When I use my 13 twist frame mount, I use 3.3 grains of Bullseye maximum for the long line and 3.0 grains for the short line. My slide mounted optic pistols have less felt recoil than my frame mount. My frame mount requires two hands to unlock slide out of battery. It locks up tight!
Slide mounted is my preference even though I’ve been shooting my frame mount for last couple of years.
Wear and tear are part of the game. Scopes get abused on the slides and recoil is harsher with a frame mount. If gun is built correctly they stay tight for many years.
One of my customers had 10k rds through his ball gun I built him. Dave Sams tested it in the HEG rest and it shot 1” group. Still really tight pistol.
Jon

Holy smokes…you can get your gun to cycle with 3.0gr of Bullseye!!! What weight bullet? 

I shot my 1911 last year with only irons and a 12.5 lb spring and had to use 4.0gr of Bullseye to cycle the gun.

When I build 1911’s I fit barrel to cycle 4.0 BE 185/200 for test fire load using 10# recoil spring; wad or ball gun. Pistol will run 3.6-3.7 after couple hundred rds. If customer is planning on shooting lighter loads I fit barrel accordingly.
My frame mount is pretty dang tight. It will run 2.8 BE in summer months. I’ve primarily used 180 Brazos and 200 Zeros in this pistol. Testing showed that with 3.0 BE 180 Brazos velocity was 622 fps. It also held X ring at 50 yds with really good lead bullets!

My ball gun builds will usually run 3.8 BE 185 jhp. I recommend this load for eic matches. Shoots on call.

Jon

I am veering a little off topic but that is ok because learning is occurring. 

With a 12.5 lb recoil spring I cannot get my gun to cycle when I load below about 850-ish fps. I have read here that others shoot in the 750 fps range but I will have to lower my spring weight to do it. I have not considered doing that yet because I figured at some point I would start to run into a situation where there is not enough spring force to close the tight gun reliably. 

What is the lowest recoil spring weight that you are willing to use in a BE 1911? 

-Trevor

Trevor, 
I try to never go lower than 10#.
Nothing wrong with down loading your ammunition and changing recoil springs to accommodate the load. That’s how it’s done!
Jon

Hey Jon, what action and mainsprings do you run with the BE 3.8? My RRA hardball functions with 4.0 N310  and 185gr JHP Noslers with WLP - any reason to go down from 14# action spring? 4.3gr for the long line based on other guidance, 4.0 at 25

SingleActionAndrew wrote:Hey Jon, what action and mainsprings do you run with the BE 3.8? My RRA hardball functions with 4.0 N310  and 185gr JHP Noslers with WLP - any reason to go down from 14# action spring? 4.3gr for the long line based on other guidance, 4.0 at 25

If it’s functioning ok I would probably leave it as is. You could try the lighter spring for comparison. A) how does slide feel when going all the way to the rear? B) how does the slide feel when going into full battery. 
Too light of spring could have harsher recoil at full recoil and heavier spring could have harsher feel when slamming into battery.
Just as Jerry Keefer was recommending, I shoot softer loads. Most cases drop about 1-2ft to the right without a shooting bench. They land on the bench. My recoil spring is allowing ejection and chambering.
Barrel fitting is more than just having a tight barrel fit. It has timing that it off can cause gun to be less reliable. Barrel fitting is an art! 
Jon

Froneck wrote:I agree with SteveT, Recoil is softer with slide mount.

Just for the record SteveT thinks a slide mount feels like more recoil. To me a light weight slide with a heavy recoil spring feels better and recovers back to the target faster.

My Mistake! But most feel the opposite, the slide mount seems to reduce recoil. A few years ago while with Adam at the AMU trailer at Camp Perry another AMU shooter asked Henderson which is better. Henderson picked up the plastic 1911 the guy next to them had for use in trying out his shooting glasses. Henderson showed the typical recoil on the 1911 with slide mount as a slow rise but when demonstrating the frame mount the gun raised and wavered like someone  firing a .50 caliber. Slide mount vs frame is like the Ford/Chevy discussion. Slide has it's advantages and Frame also. As Henderson pointed out the slide has a gentle push back and frame a sharp snap, I also agree with that. But each to their own. I prefer slide mount so does Adam for BE but his Bianchi open gun was frame mount. As to recoil spring, I prefer as heavy as possible and main spring as low as possible. I find accuracy depends on solid closing lock-up.

My mainspring is as heavy as I can make it and recoil spring is as light as I can make it. Recoil spring weight is driven by the minimum needed to chamber a round.  That is all I am sizing this spring for.   For my gun it is 12 lb. If I could go to ten I would but a dirty gun/ low ambient temps, will not always give 100% reliable chambering. After this, the main spring gets increased until rearward travel starts to become inconsistent.  Then I drop down one weight. For my gun I went to 23 pounds and still had slide energy to spare so I then went to a small radius FPS.  This was too much so I ground the radius larger and larger until I got the slide to go completely rearward again. Alternately, I could have gone above 23 on the main (and I do intend to go back to the standard FPS and try a 25 lb main to compare).  This procedure, which I did for the first time on the gun I am describing here, has resulted in a recoil impulse that rivals a slide mount. Load is 3.8 gr BE with both 185 and 200’s which are moving at 700 and 720 respectively. Just sharing this technique because it was startling how much I could soften recoil after I broke from my previous, closed-minded habit of putting a nineteen pound mainspring in all guns.  This seems to also be the most efficient and logical use of these components; recoil spring sized for chambering (going as low as the gun will permit), FPS and mainspring sized to absorb slide energy ( going as heavy as the gun will permit) and extract reliably. 
Ed

What is the difference?  Recoil spring and main spring in addition to hammer and slide cut to change slide advantage to force main spring is all the same. Assuming the hammer and slide are not changed the weight needed to unlock lugs is the total. Not that the weight of the main spring will be equal to the same weight of recoil spring so that adding 1 pound to main spring will require 1 pound of weight removed from recoil spring. Also main spring weight is variable in that because of the strut and slide/hammer contact the weight applied to the slide lowers as the slide moves back plus of course the compression weight of the main spring increases as it's compressed. In the other direction the main spring adds very little to the closing of the slide, in reality it impends it for a short amount or travel! Accuracy is dependent on the lock up, vertical stringing can result in a too low of closing pressure. Other accuracy issues can also result!
 I'm thinking as the sllde is moving back the recoil spring is increasing in compression weight and due to the mechanical advantage the slide has on the hammer is increasing the main spring effective weigh is lowering. A BE gun requires two things, accuracy and reliability! Building my .22 conversion I'm finding how spring weight is listed changes from one company to another!  Not everyone uses the same compression length at the rated weight nor can anyone tell me here in the forum what the compression length should be. So I'm building a spring compression tester! Photo of conversion and tester can be posted if requested.

I would like to see the photos of your spring tester.
Tired of playing the guess game on what weight springs I'm using.

Tester is started, I have it at my shop. I'll make photos and post it. The stand is made by Chatillon, I also have Chatillon tension/compression gauges in 10, 15 and 25lb. Reason for different gauges is as the size gets smaller minimum reading gets smaller, 10lb is in .1lb increments, 15lb is in .20lb increments and 25lb is in .25lb increments. The Stand has provisions for a digital travel indicator so I can measure spring weight at any length of compression. I plan to complete it when I finish my .22 conversion. Also have a 5lb unit I use for quick trigger pull weight but prefer the weights.

Looking forward to seeing the pictures