I just shot most of a box of factory-loaded Armscor 180 FMJ. Of 43 rounds fired in the new M40, 13 had obvious smiles and three had the first traces of smiles. Lot number appears to be 044016. Wondering if this is commonplace with all factory ammo, or Armscor in particular.
(https://farm1.staticflickr.com/805/27500218768_8434f70c77.jpg) (https://flic.kr/p/HU6NWU)
I haven't seen that before with that ammo.... Armscor is not a powerful loading in my book ( stock G20 )
Have tried many factory loads and rarely seen smiles
That seems unusual to me.
The thing with Armscor is they are using fast burning powder and as such they are high pressure loads that expands the brass before the bullet starts to move... Not sure if your lot was more than this or if they changed powders. Not sure if changing recoil springs would help in this situation.
The powder we saw in the pull-downs was TiteGroup 6.4 grains under the 180 grain FMJ
Muzzle Velocity: 1150 fps
Muzzle Energy: 529 ft. lbs
Bill you might want to remove the barrel and slide the SMILED spent casing inside looking to see if the SMILE exceeds the in battery fitment.
By this you'd be looking to see if the Smiled area as sitting inside the chamber keeps the casing from being flush to the barrel hood. If it doesn't go all the way inside then the slide & barrel moved (unlocked) while under pressure increasing unsupported areas. This situation can also affect accuracy. A change in recoils springs my actually help hold a slightly longer dwell time for lockup.
Shadow, the smiles on some cases seem to be when the slide is almost fully in battery and others perhaps a millimeter out of battery or starting to unlock, just eyeballing with my 65-year-old eyes. Looks to me like a stronger spring is indicated -- and I was thinking I wanted one anyway for the new 7-inch KKM barrel that is coming. These were the first rounds fired from an NIB, bone-stock Glock M 40. Any thoughts on a good spring weight to order?
Not sure what all is available for the G-40's, but I run a Wolff GunSprings non captive rod and 22 lbs in my G-20 and have a 24 lbs for unknown testing.
The newer Gen 4 guns have a larger purchase hole where the recoil rod and spring sits in the front of the slide, so you'll have to shop around or study what others are using.
The KKM barrel will likely solve the issues due to the tighter chamber and support.
I put a 20# spring in my G40...
With the heavy slide, red dot sight and all I believe 20 pounds its plenty for the G40.
That said, I wasn't having the issue you're having even with the factory spring... But I never shot that particular ammo either.
I got my spring and rod from NDZ Performance.
Thanks RR. Ordered that spring and rod from NDZ.
I ordered the 20lb from NDZ too
NDZ knocked my socks off with their incredibly fast service.
Yep.