I put a red dot reflex sight to my GP100 6” revolver

[Camba]

My eye sight had been deteriorating as I’ve got older and my handgun ability has gone south since then and getting worst as I get even older.
Well, I had been reading and observing of others that had put a red dot reflect sight so I had to check it out. I ended up buying a mount from Alchinguns. They have two mounts: one for RMR and another for RMSc. I thought I pressed the RMR type but found out I had the RMSc type. I’ve just went ahead and mounted in my Ruger GP100, 6” barrel revolver. Today, I took it to the range and tested some loads that were printing between 4 and 5” at 25 yards with open sights and also I loaded some 38 spc load with 125 gr Lee cast and 3.52gr of Bullseye with cci-550 primer(don’t have spp at hand).
I was able to print a group with the 158gr Speer jsp, 14.6gr 2400, and cci-500 of 1.5” at 25 yards and 1.6” with the 125gr cast, also at 25 yards.
I am happy with that but I will get some new loads to see how can I improve it and take it to 50 yards.
Have you guys done that?
I like to know some accurate loads in 1000 to 1200 fps that work well for you.
Thanks.
Camba

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[hylander]

I to am going to try a reflex on my new SBH and 686.
What Reflex did you go with ?
For very accurate loads in the .357
158 SWC on top of 6.0 Unique
or 7.2 of BE-86
Both are giving me about 1.75" @ 25yds.

[Arthur Roy]

I too have started using more optics on my handguns. I have a Holosun 507 on a 44 Contender that works really well. I also really like the Hex Dragonfly.

[Forrest r]

Been using redots and scopes on handguns for 30+ years now. When my eyes started changing (old age/40) it was time to start using redodts to stay competitive.

Started out with a 617-1 and a pro-point reddot, too much fun!!!!
https://i.imgur.com/kadBNYC.jpg

Liked that setup enough that when I was at a gunshow in 2006 (date of picture) I traded for a s&w 624, m1922 & a s&w 629 with the same pro-point reddot.
https://i.imgur.com/7dS3lgi.jpg

Used to run a cheap reddot on a s&w 41, picture taken 1-1-2006. The model 41 is between a 5-screw k22 (left) and a 4-screw k22 (right).
https://i.imgur.com/UD3hRZg.jpg

Run either a reddot (bushnell) or a scope on a s&w 686.
https://i.imgur.com/im4jQKD.jpg

I like burris reddots on the 1911's
https://i.imgur.com/8NOmyg6.jpg

Ran reddots on a marvel 1911 conversion kit, a 25m olympic sport pistol and ruger mk 2/2/4's (all 22lr pistols). Used them on contenders and a ppc revolver along with several different ar's.

You're going to find it's pretty easy to find "accurate" loads with that gp100 with that reddot on it. 2" 6-shot groups @ 50yds is extremely common. Look for bullets that that revolver prefers and then do ladder tests with them (2/3/4 bullets and the same powder/load).

For several years I bought different 35cal molds and did testing with those cast bullets in snubnosed 38spl's,2 1/2", 4" (3x), 6" (4x), 8" & 10" 38spl/357mag's. I also played around with home swaged bullets, here's some of the bullets I swaged/cast.
https://i.imgur.com/0A0Ga7O.jpg

Some of those cast bullets I owned multiple molds of. Anyway either thru not liking the bullet design or mold I thinned the herd and kept the top row 2nd bullet from left (mihec 640 series) and the bottom row center (cramer "hunter") and sold the rest off. Those 2 bullets are pretty much interchangeable in that s&w 686. Meaning same powder/same loa/same results. A chicken scratch target shot for my own amusement. The left targets (top/bottom) were shot using 5.5gr of bullseye. The right targets (top/bottom) were shot using 6.0gr of bullseye. The top (left/right) targets were shot with the hunter bullet. The bottom (left/right) targets were shot with the 640 series bullet. All 4 groups were +/- 2" 6-shot groups.
https://i.imgur.com/CfpwHXk.jpg

Nothing more than blammo ammo made with range brass. The fliers go away when I use 1x/2x fired starline 357mag brass.

That 640 series bullet from mihec is a pretty good design. That beater 629 I showed in the picture above with the reddot @ 50yds using a mihec 640 series bullet. That beater has 1 chamber in the cylinder that out of spec with the rest. Hence, 5 shots touching a 1 shot out (happens with every target I shoot).
https://i.imgur.com/AK9xTG0.jpg

Good luck and if you could post some pics of your progress.

[Bigslug]

I'm there with the automatics.

I'd comfortably go there with the hunting revolvers.

I'm not quite yet comfortable enough with the current state of durability of the optics and mounts to go there on a defensive handgun that has no provision for backup iron sights. Nobody's really thought that problem through yet, and with revolvers being largely regarded as "yesterday's combat gun", I'm not sure how many of our best and brightest minds are working on it.

But yes - I very much WANT to go there. The magnum revolvers are very much 100-yard capable firearms, and I've spent a long time working on the fundamentals that make them so. . .but aging eyes are really crashing that car, so to speak.

And even assuming the eyes are young and still work, a red dot will be MASSIVELY better for long range revolver work for three reasons:

1. You can get red dots down as small as 1 MOA. A typical front sight, designed for short range combat, held at arms length is going to cover what? 10 MOA? 12?

2. A dot will allow you to hold over your target while keeping it visible and using your target for scale. Holdover with irons involves raising blades out of notches to what you hope is the right degree.

3. When your target is so distant or so small that focusing on the front sight makes it disappear completely, the red dot's ability to allow you have sharpness of both your target and the widget you aim with becomes hyuuuuuuge.

So keep guinea-pigging in the areas you're comfortable with guys - maybe the technology will worm its way into the areas where we're currently not.

[Camba]

The red dot reflex sight I put in the GP100 is the Vortex Defense ccw micro 3 moa dot.
I am going to try the suggested loads to see how do I do with the reddot sight.

I see more red dot reflex sights for my other revolver/pistols in the near future. I had my Glock 17L already converted with the DoveMount and the Holosun 507k-x2. I need to work on new loads. The open sight loads I had were mediocre with open sights and more promising with the red dot. I like to get the Ruger GP100 done first. I meant to order the Alchinguns mount for the RMR that fits the Holosun 507c x2 that has a solar power charger so you never run out of red dot in the middle of a hunt.
I am happy that I am using again my revolvers, especially now that I can see the target aiming again.
I added some pictures to the original post to show the rig and the two groups I made yesterday.
Thanks.
Camba


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[Camba]

I to am going to try a reflex on my new SBH and 686.
What Reflex did you go with ?
For very accurate loads in the .357
158 SWC on top of 6.0 Unique
or 7.2 of BE-86
Both are giving me about 1.75" @ 25yds.

Hylander,
I went with the Vortex Defense CCW micro 3moa red dot sight.
I am going to try that 158 swc load since I had just landed an 8 pound jug of Unique powder. I have hear good things on BE 86. I just don’t have any at this time.


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[Tatume]

38 spc load with 125 gr Lee cast and 3.52gr of Bullseye

Are you really measuring charges to the hundredth of a grain precision? If so, what scale are you using?

[fecmech]

Try your Lee 125 with 4-4.2 Bullseye, consistent 2.5" 50yd groups with my K-38 and Ruger GP.

[Camba]

Are you really measuring charges to the hundredth of a grain precision? If so, what scale are you using?

I am using an RCBS automatic charger scale to measure 5 powder dumps from my RCBS manual single powder drop. I take the value the charge shows on the scale and divide it by 5 to get the average.


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[Camba]

Try your Lee 125 with 4-4.2 Bullseye, consistent 2.5" 50yd groups with my K-38 and Ruger GP.

I will try that.
Thanks


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[Camba]

I am using an RCBS automatic charger and scale. I take the value the charge shows on the scale.
Then I dump 5 consecutive charges and take the average. That is where the second decimal comes in.


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[Jtarm]

Good luck.

I tried one on my Match Champion 10mm using the EGW mount with a Swamp Fox Justice.

Dead-accurate at first, then the zero started wandering. All screws good & tight. The same sight works great on an S&W M-66 with an Alchin mount, shooting magnums.

The single screw attachment point for no-drill mounts on a Ruger just isn’t enough, IMO.

[Camba]

Good luck.

I tried one on my Match Champion 10mm using the EGW mount with a Swamp Fox Justice.

Dead-accurate at first, then the zero started wandering. All screws good & tight. The same sight works great on an S&W M-66 with an Alchin mount, shooting magnums.

The single screw attachment point for no-drill mounts on a Ruger just isn’t enough, IMO.

I am sure time will tell.
At least, for now, I can use my GP100 again and be able to feel good on the groups I get.
But, I am interested in knowing the remedy to make it a permanent mount without worrying of it moving later.
Camba


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[jdgabbard]

My eyesight is getting worse after 40, but I just can't bring myself to putting a reflexive sight on a pistol. Even having served in the post-9/11 military and having used M68s in combat, I prefer irons. It'll probably be a while before I can bring myself to using one on my rifles, let alone my pistols.