Home Forums Hunting & Shooting Handguns Glock G40 MOS sight regulation (feedback?)

Question(s) for those running the new G40 10mm:

My intended use will be boar, mostly being busted out of rocks along ridges. Running shots, in the point blank to 50 yard range. Current handgun, now retiring for G40, Bowen sighted Redhawk 44 hunter shooting 240XTP load. Last boar, typical dead run, 37 yards, one shot into vitals, and dead. On occasion, stationary boar, long shot from a steady position.

- What type of POI/POA are you seeing with the factory sights?

Blue Label guns are equipped with typical 10mm fixed sights, above the slide .165 front and .190 rear (.015" taller than standard rear). Civilian guns are equipped with adjustable. So please advise which sight, and the final measured height of the adjustable once regulated, sight in range, and load. Thanks, I will likely sight-in for a 20 yard zero, probably using a 180XTP.

If running RMR with the MOS:

- What is the measurement for the lowest sights that can be seen in the very bottom of the window?

Please advise if you are running a shim plate or not.

Thanks again, will use this info combined with my eventual results to determine needed sights. I may start off with lower sights, without RMR, then later change to taller sights, with RMR.

I'm sure there must be someone here who put rounds through the G40 with some form of fixed sights. Also, anyone running the RMR on any of the MOS models should share the same dimensions with the G40.

- any feedback on sight regulation, to get some idea how far, if any, did the sight height need to be adjusted, from the Glock standard, rear sight .025" higher than front sight, measured from top of slide.

- any feedback on sight height to be just high enough to co-witness at bottom of RMR window, when mounted on MOS.

Thanks

Gary,

No G40 MOS here but;

The extent of my experience; I've got a G29 & a G30 (which I run with 45 Supers), I've had a couple of G21's including a LongSlide (45 Super) I put together.

All of the above guns came with the +1 sight and shot high (I shoot the 200 xtp in the G29 and the 230 xtp in the 45's), I buy the '0' and the -1 cheap plastic OEM Glock sights (approx. $5) to regulate them and use the results to determine which height of steel fiber optic or tritium sights to buy.

Dawson Precision has G40 sights that co-witness and others that do not co-witness. Be aware that for some sights you have a choice of diff. front sight widths.

https://dawsonprecision.com/sights/...&category=196&is_category_page=1

Hope this may help some?

What bullet and load do you plan on using?

Jerry

Maybe this will help. With my 41 MOS and RMR 06, I ordered the standard trijicon suppressor sights. The front measures 0.350 from the top of the slide, the rear measures 0.375 from the top of the slide, but is a little hard to get exact, as the top of the rear slopes to the front.

With my 45acp and Super loads, this gives me a 25 yard zero for the most part with irons, and the red dot rests on top of the sights, perfectly. This alignment is right at the lower third line, in the RDS window.

I am running the factory MOS plate, and trijicon sealing plate, no shims needed. I cannot see the rmr sight body in the bottom of the notch, at all.

Just throwing this out for anyone reading who may not realize. The RMR is parallax free for the most part, at typical ranges. And the dot does not need to be centered in the glass window to poa/poi. The irons should work on their own for your zero, and the dot can be a little above or below the front sight.

For the RMR with sights, and if the sights are going to be the expensive trijicon nights sights, if I were worried about not getting the correct front: Buy the NS rear that clears the rmr body. Use the factory front sight on the gun with your load. Align sights shoot for target, measure the height (certainly going to be high) of hits above target. Use sight calculator to determine how high the front needs to be.

Craig

Jerry,

Mine is a blue label law enforcement packaged G40, and it is equipped with a Glock standard fixed rear 10mm +1 sight, which is 6.9/.270" w/dovetail/.190" above slide/.025" taller than front.

Was thinking it may shoot high with a hunting load, and I was looking for user feedback to see if there were any common trends with chosen sight heights to regulate. Likely, I will attempt to run a .125" wide serrated front, with brass bead as first choice, and will likely try to match it with a .125" to .150" wide serrated rear, with U-notch being first choice. Likely will hobble something together, mixing and matching fronts and rears between WC, TTI, Vogel, etc., until I find a rough and tumble combination with the best sight picture to zero my final load at 20 yards. Depending on the results with the factory sights, I'm probably looking at a 20 yard impact adjustment of 2.2" for .025" change in sight height.




Several in my circle run Dawson on their competition guns, and I do realize they make a MOS co-witness, as well as non co-witness. But, like others, such as Suarez, they make the sight universal for the MOS using all red dots, not specific to the RMR, so they are excessively tall. I will likely run dedicated non co-witness hunting sights, without mounting the RMR, as long as I can make the sight picture work for me, for a while. Likely next year, I will run the RMR, and then will mount the lowest co-witness sights I find, more so to help me track while recovering from recoil, than its use as backup for RMR failure, though that is a good benefit.




I'm sitting on a few different loads that should clock in the 1200 to 1300+ fps range in the G40, using the 180XTP, which I will test when I get a break.

Thanks for the help

Very helpful, thanks Craig!

Absent any RMR failure, followed by need to have BUIS that can be used through the window.....I mostly need the co-witness sights to aid tracking the red dot between shots while recovering from recoil. When I drive the red dot pistol out from the draw, I have no issue picking up a standard height front sight, no different than driving the gun out without RMR red dot. The pistol is driven out, I pick up the front sight, and then the window follows, and the dot is THERE. But, when running and gunning, recovering from recoil between shots, I at times can lose the dot, without having a fixed sight high enough to track in the lower portion of the sight window. But, I don't want the sights too tall so to clutter up the window. Just high enough to pick up in the bottom.


Another question:

If your .375"/.350" suppressor sights are tall enough to clear the bottom of the rear notch above the RMR body, how much lower do you think they could go, while still being able to align the tops??

Thanks again

Gary,

Hard to make a lot of measurements in the back of the gun, with the sight installed. The bottom of the notch, if held so that it is parallel with my eye, puts the top of the rmr probably a few thou above the notch. But when you align the front sight with the rear, you cannot see the back of the rmr sight.

The notch depth of the Trijicon rear suppressor sight is right at 0.100 inches.

FWIW, if your goal is BUIS only for dot re-acquisition, and no need to actually have them on for shots, you could place a white line or dot on the back of the rmr body to be aligned with a front iron sight. That would get the dot back into the window, for the transition to the dot. I have a jpoint on a 1911 slide. The jpoint has a notch in the back that looks like a rear sight. It cannot be used with a front sight for poa/poi, but is used to help me pick up the dot.

Craig

Not sure if it's too much help. I have exact same Blue Label. I ran a few 180 Hydra shocks thru it. I am printing 5" high at 25 yards. I am carrying it for bears currently(as an Offensive not Defensive). I am interested in what you find out for info. I hate to think about hold off or hold under as well.

Overall not terrible impressed with accuracy. May simply move the gun.

It will be a couple weeks before I get a break. I intend to bench the 180xtp for groups testing the different velocity loads. Will also shoot field positions, close to far. I expect the xtp will function well, and hope to determine the best load and exactly where I need to be for sight regulation.

It will be a guess at best reference the factory recoil spring. Not sure if I will have anything else on hand, other than the one in the pistol. But, I'll use a chrono to keep track of velocity spread. If I start seeing extreme spread, and smiley faces on the cases, I'll likely need to regroup at a later time using a stiffer spring. Hope this is not the case, but I will not be shocked if this happens.

As for accuracy, I've not run into any issues with Glock pistols, for obtaining a solid useable degree of accuracy. I don't expect to see precision groups, but I also don't expect to see unworkable barn door groups either. I will see, and will pass judgement then.

For an expanding hunting bullet, I like the xtp, and the 180 version appears to be near perfection for the 10mm. The velocity range for performance makes a good fit. That hydra bullet, however, is a better fit for the 40. It would need to be loaded on the light end of the 10 to prevent overtaxing the bullet.

Later