Forward slide-mounted optic?

[GlowingDonut]

I have a G22 I'd like to eventually shoot in Open, but I really don't like the height-over-bore of a C-More on an SJC mount, compared to irons. I've always liked the dot just in front of the chamber, but wondered if there's any reason why I couldn't have a slide machined to create a shallow pocket for a FastFire, or JPoint like this: (forgive the hasty G22 image flip to match the direction of the JPoint image I found)

With this location, I would focus on the dot, similar to the way I focus on the front sight post currently. I know the dot would be above the front sight slightly, but the distance would be negligible.

I've seen many JPoints mounted in the rear sight location on pistols, but like I said, I really want the sight farther down the slide.

Would machining a pocket for a JPoint in this location weaken the barrel locking into the slide?

Edited December 14, 2009 by GlowingDonut

[JThompson]

My biggest concern would be ejecta from the chamber, the slide would be moving back into it. Really, you would need to try it and see. I don't shoot down new ideas until there is empirical data it won't work or has to many drawbacks.

JT

[BritinUSA]

I've seen some CZ's setup like that for IPSC Modified Division. They use a low scope mount to do it, instead of milling the slide you could make up a mount that attaches to the frame-rail.

[01G8R]

With this location, I would focus on the dot, similar to the way I focus on the front sight post currently.

I think when shooting with a dot you should use a target focus instead of focusing on the dot. With a target focus that would make the dot location (front to rear) on the pistol less significant. I would also think the field of view through the J point will get smaller the further you get it away from your eve. That might make it easier to lose the dot. I'm not trying to talk you out of it, just giving some things I thought about. If you decide to do it I will be interested in how it shoots for you.

[TeamGE]

Shooting with a dot means focus is on the target. Moving the dot 3 inches forward or back-wards will make very little difference in dot size or window size when using it at arms length such as in a pistol mounting. I would not recommend machining a pocket that close to the lockup edge for mechanical strength reasons, but mounting it directly to the top of the slide would be OK.

[BritinUSA]

Here's a picture of a forward mounted red-dot on a CZ

[GlowingDonut]

Sorry all, yes you are correct: dot should have a target focus. I said dot focus rather than front site focus. Thanks for the input so far.

[GlowingDonut]

Here's a picture of a forward mounted red-dot on a CZ

THAT is the ticket! Problem I see with a G22 frame vs. the CZ is drilling into polymer isn't really a solid solution to mount with screws. Maybe like a Carver mount, but much lighter weight (with no rear torque arm) and a super-low platform for a Jpoint in the same location would be a perfect solution.

[BritinUSA]

As I said in my first post, you could make a mount that sits on the frame rails.

[nphd2000]

SJC makes a mount for that.

[supreme135]

I have a G22 I'd like to eventually shoot in Open, but I really don't like the height-over-bore of a C-More on an SJC mount, compared to irons. I've always liked the dot just in front of the chamber, but wondered if there's any reason why I couldn't have a slide machined to create a shallow pocket for a FastFire, or JPoint like this: (forgive the hasty G22 image flip to match the direction of the JPoint image I found)

With this location, I would focus on the dot, similar to the way I focus on the front sight post currently. I know the dot would be above the front sight slightly, but the distance would be negligible.

I've seen many JPoints mounted in the rear sight location on pistols, but like I said, I really want the sight farther down the slide.

Would machining a pocket for a JPoint in this location weaken the barrel locking into the slide?

Glock Worx can do the milling. They did mine on the rear of my G17 and it was perfect. I don't know that there is enough meat up front. SJC has new mounts I would take a look.

[want2race]

The further away from the pivot point (wrist) the higher the dot will rise and fall.

[Aircooled6racer]

Hello: You can put the dot there if you want. I would just buy the J-Point mount that fits in the rear sight dovetail and call it done. That is what I have on my G17 steel pistol. Works great and I can take the J-Point off and install it on my Mech-Tech 9mm with another mount. That reminds me I need to get a Weaver mount for my J-Point Thanks, Eric

[The Antichrome]

SJC makes a mount for that.

http://stores.sjcguns.com/Detail.bok?no=77

[GlowingDonut]

Thanks for the link to the SJC mount. I read the page, but I can't figure out if you need to drill a hole in the frame to mount it? Looks like it uses the tigger pin hole, and a second one, to mount.

[nphd2000]

You need to drill the frame for the SJC mount. I have two.

[rvb]

The further away from the pivot point (wrist) the higher the dot will rise and fall.

Trying to wrap my head around this statement....

The dot is pointing where the muzzle's pointing, so the dot rising higher implies more muzzle rise. How does moving the scope make the gun recoil more?

Or are we not talking about the same thing?

-rvb

[Doug H.]

The further away from the pivot point (wrist) the higher the dot will rise and fall.

Trying to wrap my head around this statement....

The dot is pointing where the muzzle's pointing, so the dot rising higher implies more muzzle rise. How does moving the scope make the gun recoil more?

Or are we not talking about the same thing?

-rvb

If the muzzle moves the same angular distance, say 10 degrees, the farther away from the pivot point you get, the more the dot will appear to move. You can test this by taking a 12 ruler and holding one end by your nose, this will be the pivot. Take your other hand and hold about 6 inches down the ruler and pivot the ruler up 10 degrees. You will see that the far end of the ruler appears to be higher than where your fingers are holding the ruler. The ruler is at the same angle, but the farther away from the pivot the higher something, like the dot, will look.

Doug

[rvb]

The further away from the pivot point (wrist) the higher the dot will rise and fall.

Trying to wrap my head around this statement....

The dot is pointing where the muzzle's pointing, so the dot rising higher implies more muzzle rise. How does moving the scope make the gun recoil more?

Or are we not talking about the same thing?

-rvb

If the muzzle moves the same angular distance, say 10 degrees, the farther away from the pivot point you get, the more the dot will appear to move. You can test this by taking a 12 ruler and holding one end by your nose, this will be the pivot. Take your other hand and hold about 6 inches down the ruler and pivot the ruler up 10 degrees. You will see that the far end of the ruler appears to be higher than where your fingers are holding the ruler. The ruler is at the same angle, but the farther away from the pivot the higher something, like the dot, will look.

Doug

That makes sense for iron sights, but for a dot, well, the dot points where the gun is pointing... if in recoil the gun rises from the middle of the lower A to the upper A, then so will the dot, regardless if you hold the scope at your nose or 3 feet out, that's where the gun is pointing. Might look a little different in relation to the lens, but I don't think that's was meant? Or maybe it was? Maybe want2race meant the "scope" would rise higher when he said "dot?" That I can get behind.

-rvb

[cybrosh]

Good day,

I don't think you have enough metal on the front to add a red dot sight.

In addition, I have little faith in red dot sights mounted directly on slides. I've seen too many die, while the ones mounted kept on going up until this day. I would buy an extra red dot or even more. In my opinion, mount is the way to go.

[JeffWard]

The further away from the pivot point (wrist) the higher the dot will rise and fall.

Beat me to it.

There's much more barrel rise than "rear-of-slide" size on a non-comp gun. The dot will move more and more, the further it is from the back of the slide. Since your eyes are target focused on a dot-gun, the farther back the dot is, the more stable it would seem to be to the shooter's eye?

Never shot one, just imagining the gun physics.

Jeff

[GlowingDonut]

So, dots mounted on a frame mount over the front of the chamber (like a C-More on a frame mount) would seem to exhibit this same amount of additional dot movement, compared to the "rear sight" location. I guess I'm confused why so many shooters put the dot out ahead of the chamber on 2011 guns in a similar, non-slide-mounted position, and they're perfectly fine with the additional dot movement stated above. My initial idea was to combine the location of a traditional frame mounted C-More, on an ultra-low slide mounted Jpoint, to bring the sight plane down as close to the bore line as possible, similar to iron sights.

[notasccrmom]

There isn't enough meat in the slide to mount it up there. It's pretty thin. The usual rear sight area has a lot more material.

[nphd2000]

You could probably drill and tap holes in the top of the slide to match the j-point pattern. Make sure the fasteners don't protrude below the thickness of the slide. I have a carver mount that puts the c-more forward of the ejection port. I don't like the way it balances and if you look at the open guns on his website the c-more mounting plate is redrilled and moved to the rear. If the gun is sprung correctly with the right load I don't think you would have much more dot movement. JMO

[rvb]

The further away from the pivot point (wrist) the higher the dot will rise and fall.

There's much more barrel rise than "rear-of-slide" size [rise?] on a non-comp gun. The dot will move more and more, the further it is from the back of the slide. Since your eyes are target focused on a dot-gun...

So, dots mounted on a frame mount over the front of the chamber (like a C-More on a frame mount) would seem to exhibit this same amount of additional dot movement, compared to the "rear sight" location.

So I'm curious... would you guys have the same opinion if we replaced the red-dot scope with a laser? Would you say the dot from a laser would have more rise depending on how far forward it was mounted (ie grip mounted vs guide-rod)? If yes, then why? If no, then why is a red-dot scope any different?

imo: In both cases the sight is always the same distance from the pivot point (on the target!). It's not like irons where you're looking at a point at some variable distance between you and the target. It seems that a dot from a laser would rise the same no matter where it's mounted since it's always pointing in line with the gun. I don't see a dot scope working any differently (ignoring parallax). Or after all this time do I not get how a dot scope works?

-rvb

Edited January 11, 2010 by rvb