Natural pointing 1911 vs

A conversion unit? It seems that for the same grip, wrist angle, and stance, a Marvel ( in my case) points differently.  What say you?

Hmmm. Conversion rail is parallel with barrel/bore. 1911 barrel is 1 degree higher in the rear. Optic rail mounted on slide has taper to accommodate the the 1 degree. Some rails are tapered more than others. So yes vertically it can be different.
Jon

I don't notice any difference..........

Ric

The same lower in both cases?
If so, it must be weight and balance. And maybe sight configuration.

If different lower and grip panels, are the panels the same thickness and taper at the front and rear.

Could you describe or characterize what "points differently" looks like to you? 

For me the conversion raises to the same point of aim. but i perceive that the conversion wants to point slightly lower. This, I think, is due to a completely level sight rail on the conversion.

I feel that the angle to the sights is different. 

I somehow thought the 1911 rib or rail had a bigger taper to it than 1 degree, 11 comes to mind. Then there is the barrel axis angle to the rib. I didn’t try to measure anything. It just feels different. Thanks

Though I never measured the barrel angel of the 1911, it must be near 1 degree, definitely not 11 degrees! When making slide mount scope mounts 1 degree is often used. It's done so that when mounting a red dot elevation adjustment is not exceeded. At 1 degree the barrel will be pointed 31.4" below center at 50 yards.
 As Jon said the 1911 barrel is at an angle and the conversion barrels are not. .22 and 45acp trajectory are similar depending on bullet weight and amount of powder. Therefore the tilt of the frame must be greater on the 1911 45acp.

Cat logged me out before I could send ... oh well, I needed to get some rubbing in on him anyway. He's shown me keyboard shortcuts I didn't know existed.

My sight rail is .5° with respect to the top of the slide. I think I got that from measuring the iron sights. Or rounded off to use my 30' soft jaws on the mill.

Top of the slide is .5° with respect to the frame. So the base is 1° to the frame. The breech face and barrel are at .87°, so there's .13° elevation built in.

Parts modeled from the Mil dwgs. There's some interference at the rear lug, and about .018" clearance at the slide stop.

I shoot a Nelson on my .45 lower, and it does feel noticeably different than the .45 slide. What stands out to me the most is the way they balance. The Nelson feels heavier than the .45 slide, feels muzzle heavy, even though the overall weight is within an ounce. Also the optics sit higher on the .45 slide with a slide mounted rail. I do prefer the feel and balance of the .45 slide compared to the conversion.

BHeintz wrote:I shoot a Nelson on my .45 lower, and it does feel noticeably different than the .45 slide. What stands out to me the most is the way they balance. The Nelson feels heavier than the .45 slide, feels muzzle heavy, even though the overall weight is within an ounce. Also the optics sit higher on the .45 slide with a slide mounted rail. I do prefer the feel and balance of the .45 slide compared to the conversion.

The barrel weight of the nelson is greater than that of a 45 barrel. I don't have my spare 22 barrel handy but between a 9mm and 45 barrel (both kkm), they are about 1.5oz different in weight.

Breach face is  0° not .87°. 1911 drawings at https://www.m1911.org/M1911-A1_REDUX.pdf show breach face .87° back from 90° from reference F which is probably the design angle of the 1911 barrel. If the barrel angle was .87° then barrel will be pointed 27.33" below center. I don't see any compensation except difference of height between front and rear sight.

Slide rails are not parallel with the top of the slide. Slide tapers down from the rear. I’ve never measured the angle. Guess I should some time.
Jon

Maybe tomorrow if I get a chance I'll measure the angle. Centerline I refer to is the rails, being the rails are the same on both the conversion and the 1911 due to the difference in the barrel and slide, frame remains the same. Therefore the frame that's held by the hand has to be tilted more when shooting the 45acp.

I did some quick measurements on some new never used Caspian slides I have. Angle to the top of the slide to the rail is from .25° to .32°. Angle of breach face to rail using Starret359 precision vernier protractor was 0° but will double check with dial indicator in Moore Jig Borer spindle. Will turn rod to fit in barrel so as to measure barrel tilt angle using dial indicator in the Moore.
So with out any taper in a slide mount the angle will compensate for about 10" at 50 yards.

Yeah, before the cat erased my post, I had some sort of reference to the .87° of the breech face being 90° from the barrel axis the lug recesses are cut on.

Although, 'upon further review', I think you may be right about the breech face being 90° to the frame rail, and the barrel tipped up so the base of the cartridge IS NOT square to the breech when fired. Weird. If anything, I'd think they'd tip it the other way to assist feeding. Of course the cartridge isn't 'level' when it's being pushed out of the magazine anyway.

No doubt there's variation part to part. The other unknown is the actual lug engagement and how that sets the barrel angle with respect to the frame rails. I won't be a bit surprised if you find it some noticeable amount off from .87°.

Jon Eulette wrote:Slide rails are not parallel with the top of the slide. Slide tapers down from the rear. I’ve never measured the angle. Guess I should some time.
Jon

Jon, does any of this matter when a person gets used to any given gun for shooting?  Maybe I'm just nowhere even close to good enough to notice a difference like that.  None of my 1911 guns feel "the same".  There are so many things that can feel different.  Once the gun is sighted in for any given user (let's say you) does this possible difference in angle matter?  


I assume you shoot both open sights and dots.  I remember how you are very picky about which dot sights you're willing to use, and Ultradot sights are not on that list.  (One of my issues is my inability to find any other quality manufacturer who makes red dot sights similar to the 30mm or 1" Ultradots.)  I've always wanted to ask you what kind of glasses might allow shooters to use open sights as well as when they were younger - one of these days, I'll do so.



I guess this topic doesn't apply to me - I bought my Nelson Conversion with a rail on top, and all that matters is where the dot is, and stays, as I shoot.  I've found that none of my short red dot sights work as well as a tube-style sight such as the ones from Ultradot, and while I've got a 30mm sight mounted currently, I will be replacing it with the smaller and lighter one inch model.

For me, the small red dot sights including the Aimpoint H-1 and H-2 aren't as "stable" as the long tube type sights.  Larry Nelson understood what I meant, and after my last call with him I was going to test the shorter sights, but with one of the two Nelson weights screwed onto the end of the barrel.  For me, with the Ultradot, the gun feels "stable".  For me, with the Aimpoint, my view through the sight can "quiver/vibrate".  

As a test, holding the gun up in front of me, with the Aimpoint, given the tiniest amount of "shake" as I hold the gun, the dot wants to move all over - but with the longer tube type sights, the dot feels "glued in place" and if it moves away, it wants to go right back to being centered.  It's like an out of balance tire on a car wheel - at a particular speed the tire/wheel/car shakes violently, but at other speeds, it is smooth as can be.  

Anyway, back to this topic, I don't have a Nelson Conversion with open sights, so I don't have anything useful to say here.  I'm too stubborn to give up on open sights, and I'm dry-firing every day with open sights on my 1911 9mm, and I would be thrilled if I could shoot with them just as well as with a dot.  Regardless, the heavier the gun, the smaller my group.  Maybe it has to do with inertia......