My experience: The Gen 3 Springfield mount is much disliked as this thread indicates. I inherited one of the Gen 3 and when the big attachment screw snapped off, I sent mount and rifle back to SAI. Two weeks later , all was returned and the mount has stayed on tight ever since. Its a cast part so that screw is problematic. I have been waiting now 8 yrs for a reason to replace this mount and have not had a reason to arise. I admit my report here is an exception to the norm and if one is shopping for a mount, don't go with a SAI who is now on GEN 4. Sadlak and Basset and Smith Enterprises didn't take 4 tries to get their mounts right so take a hint of the obvious here. Regardless of you choice of mount and height of rings, you will shortly find out you have to have some sort of cheek riser if you intend to shoot accurately with a M1A scoped. Scoped, the M1A is a very accurate rifle and ergonomics good to 600 yds. At 800 yds and 1000 yds, the drop of the stock is all wrong and its awkward to shoot it well.
If shooting 150 or 168 gr bullet loads, little risk any mount is going to come loose but heavy 175 gr loads will shortly show you if your mount will come lose in short order. If it does, its the mount design, not a reason to cease shooting 175's.
Sadlak sells a Nat Match "grooved" gas piston which dampens recoil and I'll warn you, this item is very problematic. Your accuracy will be degraded some which is insignificant at 600 yds on big CMP / NRA bullseyes with huge scoring rings. I found out trying to shoot at 1 MOA targets at 1000 yds , this NM gas piston ruined my accuracy and I re installed the original gas piston and long range accuracy was restored. I called Sadlak to talk my issues with this NM piston (ain't cheap) and after some humm haws , the tech rep admitted what I experienced is a common occurrence. Save your money and avoid this NM grooved piston.
My M1A is a stock model, circa 1991, has the 3 Gen SAI mount, SWFA rings, SWFA 16x Super Sniper scope on it. I can hold a 18" group at 1000 yds when I do my part. I can almost always keep all rounds in a man size E Silhouette military target at this distance. Angle of man is the yard stick I use to call success for this rifle and the Mk316 Mod"O" load that I use. I have been using the original formulation of this M316 load which was 41.745 grains of IMR 4064 but current lots of military issue seem to have changed the powder to 43 grains per internet chatter. I can't comment the dividends gained by that newly reported loading but I will work up to it and see if it has merit. At present, the original loading by the military (which is not a hot load) is superbly accurate and as stated, 18" groups at 1000 yds with it out of a plain jane tier M1A is nothing for me to snivel about, I'm good with it.
Any of the recommended mounts in this thread are good investments. Can't recommend SAI mounts , lots of baggage on them is warranted and who wants to bet they got it right with their GEN 4 ? If my Gen 3 SAI gives me any issues, its replaced immediately.
Not at all!
Anybody want a "slightly used" SA mount? Seriously, I wouldn't sell this to anyone. My reputation is more valuable to me than the couple of $ I'd make sloughing this on some unwitting buyer.
I mentioned my preference for the Basset low Picatinny mount. The tall version does indeed let you use the iron sights, but at the need of using a cheek pad or comb riser of some sort for comfortable scope use. My second Bassett was the low mount, and since it is fast and easy to remove and remount, the ability to shoot without needing a comb riser is a big plus. I should note that I have an M14E2 stock, so YMMV.
Thanks Leon, you describe an issue I have with the slot. The mount is damaged in that spot. While the mount currently seems tight, accuracy is not there.
It's beginning to look like I need a new mount.
In the way of follow up. The M1A is a semi-auto clone of the US M14. The Army has a sniper version of the M14. Is the GI mount available in the civilian market? Same company, same mount? That would seem like the ultimate setup.
There have been quite a few different scopes and mounts used on the M21 over the years. You can find original USGI mounts but they are $$$$ and may not be as good as some of the more modern options unless you are trying to build a period correct replica.
I went with the ARMS 18 mount as I found out that the US military used them at one point in time. I can't recall when, now, though. I figured if it was good enough for service use, it's more than good enough for my needs!
That maybe why the SA instructions require the base be peened to the receiver. Or so I read online. I never got that far with mine. I dont even remember if mine came with instructions. Should have. I doubt many hammer the mount to set it in. I know I might hesistate or fail to read those details.
There is a reason that the "OEM" mounts come free with the guns, and are $30 at the gun show......It's because they're cheap crap and suck ass. All of them. I ritualistically throw them in the trash so I'll never be tempted to waste my time and ammo trying.
ARMS and SADLAK rule. I haven't personally used Bassett but I hear good things.