.357 sig Bullet set back after put into battery?

[XL6504ME]

Is it normal for a round to set back a little after going into battery? I just started reloading .357 sig with a 650 , 124 grain bullet flat nose tapered RMR, 12 grains of # aa9 , cci 500 and speer case. 1.140 oal after I but it goes into battery then remeasured it's a few thousands shorter on the oal is this normal ? I might add that it has a very slight crimp.

[Sarge]

Not normal at all. Take barrel out drop round in should plop in and fall right out when inverted. If no plop or hangs up when tipped it's too long and bullet hitting lands

[mrpredictable]

I've had .357 sig set back a lot easier than other calibers. Minor malfunctions and such.

[superdude]

Some amount of setback is normal when feeding many pistol cartridges. A couple thousandths is not a problem, but the greater the setback, the higher the pressure increase. The concern with the SIG round is that it has such a short neck and offers little case tension compared to straight-walled cartridges. Are you applying any taper crimp to reduce the change of setback?

It looks like your load is well below max, so just keep an eye on it and watch for pressure signs.

[XL6504ME]

Not normal at all. Take barrel out drop round in should plop in and fall right out when inverted. If no plop or hangs up when tipped it's too long and bullet hitting lands

when I drop the round in the barrel it plops and falls right back out. so it's not wedging in so maybe I'm not getting good measurements. I will recheck again .

[XL6504ME]

Some amount of setback is normal when feeding many pistol cartridges. A couple thousandths is not a problem, but the greater the setback, the higher the pressure increase. The concern with the SIG round is that it has such a short neck and offers little case tension compared to straight-walled cartridges. Are you applying any taper crimp to reduce the change of setback?

It looks like your load is well below max, so just keep an eye on it and watch for pressure signs.

Yes just a small amount of crimp, I did quite a bit of research on the .357sig here trying to head off any problems . so maybe just the way it goes up the feed ramp ?? it's not much but maybe I'm being a little to critical. thanks for the reply

[superdude]

Not normal at all. Take barrel out drop round in should plop in and fall right out when inverted. If no plop or hangs up when tipped it's too long and bullet hitting lands

when I drop the round in the barrel it plops and falls right back out. so it's not wedging in so maybe I'm not getting good measurements. I will recheck again .

Setback typically occurs when the bullet nose hits the feed ramp and the top of the chamber during feeding.

[Gooldylocks]

Not normal at all. Take barrel out drop round in should plop in and fall right out when inverted. If no plop or hangs up when tipped it's too long and bullet hitting lands

Very normal.

357 is notoriously bad about bullet setback. You should try a lee factory crimp die. Unlike the straight wall caliber FCD's, the 357 sig die is a collet crimp, similar to a rifle. Works way better than a taper crimp.

Also, if you are using 9mm bullets, they are likely tapered on the sides. using a sig specific bullet with parallel walls will also crimp better.

Using bulky, slow powders like the AA9 will help significantly, so that if a bullet does setback it will rest on the powder charge.

Source: my buddy and I just went through this with his gun.

[BeerBaron]

Using sig brass or 40 cal necked down? The 40 cal when necked down does have a shorter neck and thus less neck tension.

Plenty use 40 brass without issue but you need to ensure size die is giving correct neck tension and that oal and crimp are correct.

[9x45]

I have been loading .357SIG for about 6 years. Bullet setback is a concern because of the short neck and most guys tend to use 9mm bullets instead of .357SIG specific. I load on a 550 and always push the bullet in hard at the seating station, and more than once it's gone all the way in. Montana Gold 125JHPS (.3555") and once fired Speer Lawman brass. Load is 7.8 grains of BE-86 at 1.140" I also use a Lee "factory crimp" die, it's really a floating crimp, because you don't have to worry about small variances in cases length. The .357SIG only needs the very, very slightest de-bell, unlike 9mm. In fact, some rounds will barrel chamber check without crimp at all. Setback does not occur when the round hits the feed ramp, not in a Glock, because the nose never touches it. Now, much more important than any of that, is duty rounds. They only get chambered one time. When I unload for a match, the first bullet out is the first one fired in the match, it never gets twice chambered. And I have seen them go down by .025" on other Glocks after only a few trips thru the chamber after cleaning.