What is the maximum allowable weight for an optic mounted on the Sig P322 slide?

No one will be able to answer that.

Best reasonable answer is that if it fits the footprint it’s probably fine.

quote:

Originally posted by pedropcola:
No one will be able to answer that.

Best reasonable answer is that if it fits the footprint it’s probably fine.

Someone at Sig should be able to answer it since the pistol was designed and made here in the USA by Sig. It's relevant too as there are currently efforts to make optics with other footprints work on the P322.

Well good luck with your search. Heads up, if you think someone at Sig will answer that definitively then you ought to call Sig. They ain’t gonna answer it here.

As long as the weight of the optic + fasteners + any adapter plate is less than the total weight of the compete slide assembly it will cycle fine. No modern optic - mounting assembly weighs that much!

The weight issue is critical for Benelli inertia-bolt shotguns when folks start adding 3-gun accessories. I mused on this topic in an extensive technical Benelli Manual I authored many years ago. The physics remain the same as when Newton was sitting under the apple tree.

Extensive testing in ballistics labs and repeated field-testing of our line produced
weapons put at 180 kgm the lowest level of kinetic energy that must be generated by the cartridge 12 gauge and at 125 kgm for 20 gauge to fully cycle the action (the measurement was taken on a manometric barrel, according to at a velocity of V1 at 10 meter distance from the muzzle). Empirically, Benelli has determined the minimum threshold of kinetic energy required to cycle the bolt; the rest of the understanding is simple mathematics / physics.


KEMin = ½ m VMin2 KE=kinetic energy m=mass of gun
V1 = Vmin = minimum cartridge power to cycle M1 action

V 1 = √ 2 * KEMin ___
m1

When the mass of the gun is increased = m2 ; V2 will be LESS than V1


V 2 = √ 2 * KEMin ___
m2

Because V2 is less than V1, the minimum amount of kinetic energy to cycle the inertia bolt mechanism is not generated.

The Benelli M1 20 gauge inertia bolt weighs 385 grams.

Two 20 gauge cartridges weigh 65 grams
Two shot magazine tube extension weighs 300 grams
Total = 365 grams

So, a 2 shot extension tube with cartridges is within 20 grams (2/3 of ounce) weight of the inertia bolt weight.

The attached may assist in understanding how adding weight / mass to the inertia platform may interfere with reliable cycling operation. The 20 gauge M1 bolt weighs 385 grams; a 2 shot magazine tube extension weighs 300 grams Plus 65 grams for the 2 cartridges and you have 365 grams of extra weight; almost the weight of the bolt.

Third parties cite Benelli sources as stating that ~ 500 grams of added weight (1.1 pounds) begins to reduce reliable function. A 12 gauge 2 shot extension and two 3" cartridges is just about 500 grams......again, just about the mass of the 12 gauge inertia bolt.

So, the addition of the 2-shot extensions plus the cartridges do not exceed the bolt weight, but add a Picatinny rail and a light etc......therein the problems of operation may begin to be experienced.

quote:

Originally posted by sigwerkes2:
As long as the weight of the optic + fasteners + any adapter plate is less than the total weight of the compete slide assembly it will cycle fine. No modern optic - mounting assembly weighs that much!

What is your basis to say that so long as one does not double the weight of the slide, all will be fine?

I agree that it’s very unlikely anyone here can provide a knowledgeable answer to the original question. We have had some SIG “insiders” as members at various times over the years, but they don’t last long either because how they’re treated by the rest of us or, possibly, because the company discourages their participation. Like so many questions that get asked, how could anyone know without extensive experimentation with all the variables: weight of the sight, power of the ammunition, prior usage history of the gun, status of the gun’s maintenance, how the gun is handled and shot, and possibly things I’m not even aware of—?

The gun is still relatively new, and in time we may see reports of problems as some of the variables are applied in actual use, but it’s probably a little early for that yet.

Someone could of course do everyone else a favor: Buy a couple/three guns (or more to ensure that whatever results were obtained weren’t due to some quirk of an individual specimen). Then acquire a good selection of the many suitable optical sights available and test the supply of guns with all the sights, and of course, with a representative sample of the various types of ammunition available. Ideally the tests would be conducted with different shooters and levels of maintenance, different lubricants, and so on.

A report after all that would be well received, I’m sure.

Or someone could try calling SIG and asking the question. I would be astonished if the rep who answered the phone would have any idea or even make the effort to try to find out, but it’s just a phone call.

I'm pretty certain there is more than one design engineer for the P322 that knows what the maximum slide weight (including mounted optic) is for reliable operation. However, as you suggest, most companies are reluctant to mention any product's constraints.

I have asked this question of Sig. I have not received a reply yet, and will be pleasantly surprised if I do. :-)

not a chance in h*** sig will give you an answer. none, nada, zero. Also not a chance they have ever conducted a trial to test this. Why anyone would expect them to know is beyond me.

quote:

Originally posted by hrcjon:
not a chance in h*** sig will give you an answer. none, nada, zero. Also not a chance they have ever conducted a trial to test this. Why anyone would expect them to know is beyond me.

You don’t think in all of their R&D they did not determine a weight range that the slide assembly would need to fall into for the gun to operate properly?
Whether they tell you the answer or not is a different story but I am going to guess they have a pretty good idea at what weight the slide assembly becomes too heavy for the gun to cycle properly.

The fact that adding weight to the slide has a direct impact on the guns function and the slide is milled from the factory for a dot. I would bet the tried numerous different weights in the milled area to determine how much it could handle before the gun would no longer reliably cycle.

Granted I am not an engineer but I am guessing this would be something they tested and a very simple test at that.

I bet they ran their Romeo series sights on it and called it a day. Maybe a Holosun since they fit too. Too many variables otherwise. Ie, heavy sight and high velocity works, lighter sight and standard velocity, etc. They probably picked the sights they milled it for and tested it. If it ran fine it went to market.

It would be easy enough to test this just by stacking plates on the gun till it stopped working. You need some basic machining skills. Why anyone would give a shit is a whole other matter. lol

"You don’t think in all of their R&D they did not determine a weight range that the slide assembly would need to fall into for the gun to operate properly?"
Nope, nope and double nope. I would bet money that they got a selection of the most popular sights that might fit, some ammo across the spectrum of velocities, the sig suppressor and told the design guys to make these run acceptably. Not a chance they did any study to find the weight needed for a given combo of slide, ammo, suppressor, temp, altitude and the zillion other things that matter for these. This is a low cost pistol design and I bet the R&D budget was (correctly) aligned with that goal.

Sig has over 300 engineers working for them. But some of you think Sig has no idea of the slide's max weight - amazing.

You seem kind of insistent on this issue so let me summarize all the input for you.

No, they don’t care. It’s a cheap rimfire design. It works with the optics that currently are on the market that have the correct footprint. This isn’t some specwar contract. It’s a plinker. It works with the micro class red dots. So no, their 300 engineers probably have jobs that they get paid to do that don’t include figuring out if a big ass optic will work on their little 22 plinkster.

You could easily do the science experiment with stacked metal plates if you are dead ass determined to know the answer. Why you give such a shit still eludes me though.

If you do figure it out though, just remember, we do love pictures. lol

P322 sales will insure that Sig cares.

Also, some third party folks care:

https://taccom3g.com/product/r...-plate-for-sig-p322/

You have that completely backwards. Sig P322 sales are robust, why would they put a nickle into answering your question now. And for sure they didn't test for it when they designed it either. The major market micro optics run. The fact that there is a third party mounting plate for other optics is a great part of the optics world with CNC machines everywhere, but its totally and completely on you or the 3rd party to determine if what they are selling works. Sig is not in any way saying you can get (some odd ball and heavy) optic to run on the P322. And they won't. And they won't tell you a maximum. I don't get why you care but if you do then just mount up a small test and have at it as pedropcola says. If you want to mount an acog on one your going to have to figure it out yourself.

Slide mounted optics on a 22 LR is new. But Sig is not alone and more competition is coming:

https://fnamerica.com/press-re...-optics-ready-22-lr/

Fair enough on the first sentence. But why don't you see if FN will answer your question on the max weight. And while your at it give glock a call I'd like to run an optic on my G44 and it would be nice to know what the max weight could be and still get it to run.

quote:

Originally posted by hrcjon:
You have that completely backwards. Sig P322 sales are robust, why would they put a nickle into answering your question now.

Because more options for 3rd party optics means more sales.

You do have this backwards. They are selling every one of these that comes out of the factory. Every one. They have no real serious competition in this class. Taurus and FN. The Taurus is a Taurus and the FN holds 25% less and FN is never selling handguns at the Sig level. They don’t care if an SRO works on this. They will not worry until someone who isn’t Taurus comes out with a reliable 20 rounder.

As for your plate, it’s on sale already. Go buy one and mount anything you like. If it doesn’t run you are only out 30 bucks. Consider it a win.

I direct mounted a 507k. Easy, low, like it was made for it. Oh, because it was.

Seriously to answer your question, nobody can answer definitively. You hate that but you gotta learn to live with life’s limitations. That being said, lighter is always going to be better on a 22 slide. Hard to beat physics. As you go heavier your margin for reliability will shrink. Not may shrink, but will shrink. Best bet? Pick your micro of choice and have fun. It’s a good time to be a 22 guy.