9mm Slide not locking back

[glug]

I've been running the same 9mm load for a long time out of my G23 with Lone Wolf 9mm conversion barrel and it works great:

115gr 'Parabellum' LRN from Missouri Bullet Company
4.7 grains Win 231

Problem is I worked up to the same load in my G17 (also with Lone Wolf barrel) and the slide almost always fails to lock back on the last round. At this point I'm close to max load and at min OAL already so I'm not sure why it's having trouble. Maybe the powder is going bad? I've had the jug about a year now and I store it in my garage which is maybe not the smartest, gets kinda warm in there.

I tried changing the projectile to a Berry's plated 115gr RN to see if it was the bullet and had the same issue. I even tested it my in G26 to make sure it wasn't the gun and the G26 wouldn't lock back either. No idea why the G23 is immune.

Should I try increasing the charge beyond the book maximum in small increments?
More crimp?

I could always try a heavier bullet but I'm trying to keep costs down and the 115s are the cheapest (plus I still have a lot of them).

[Citadelgrad87]

Does the same magazine and weapon lock back with factory loads?

My first thought is bad mag spring, follower, or an issue with the slide lock.

[rm1911]

first thought is bad mag spring, follower, or an issue with the slide lock.

This

[J-cat]

Or the mag catch.

[Kmai24]

This may be way off but is a possibility..
Is it possible you have your thumb riding on the mag release? Not saying you don't know how to hold your gun correctly but I've seen it happen also I've been a culprit of this before. I don't own any glocks but I do own a few different guns in the same caliber and I always test each gun with the same load and each gun functions fine. I don't think it's your load rather a mechanical error with either your gun (mentioned above) or that crazy possibility that I suggested??

[CEDaytonaRydr]

My first thought is bad mag spring, follower, or an issue with the slide lock.

Usually this^^

If the loads have the ability to strip a fresh round from the magazine during firing, it should have enough "umph" to lock the slide back on the last round.

[Leethe4th]

Check the slide stop also. I had a G17 where the little wire spring was just completely soft. Replaced it and worked fine.

[glug]

Pretty sure it's not the gun at this point. Never had any trouble with it using factory ammo, and the slide lock problem happens with the reloads on all 6 of my mags. Also the fact that it happens with the plated bullet on my G26 (couldn't test the lead bullet with the stock barrel).

I guess I need to get out there with a chronograph and see what's going on. If it does turn out that it's underpowered I'm just wondering how I can correct it since I'm already near max load. Wondering if more crimp would make any difference.

[Bastard]

might sound a bit counter intuitive but have you tried lowering the charge?

you worked the load up using .40 recoil springs (unless you changed them) and in the 9mm it might be cycling too fast or something like that.

[CEDaytonaRydr]

I guess I need to get out there with a chronograph and see what's going on. If it does turn out that it's underpowered I'm just wondering how I can correct it since I'm already near max load. Wondering if more crimp would make any difference.

Probably not. In fact, if you're close to max load, and you're using plated bullets, you could over-crimp, mushroom the projectile, and cause a potentially dangerous over pressure situation.

You say you're using a wolf barrel? Are you de-glocking your brass?

[glug]

You say you're using a wolf barrel? Are you de-glocking your brass?

Not de-glocking. I was under the impression that's not needed with a Lone Wolf barrel since it has a fully supported chamber.

In general I didn't think it's necessary for 9mm at all, only ever heard of people doing it for 40 Cal.

[glug]

might sound a bit counter intuitive but have you tried lowering the charge?

you worked the load up using .40 recoil springs (unless you changed them) and in the 9mm it might be cycling too fast or something like that.

That's a great point. I did start over when I tried the plated bullets and had the same issue though. I guess I could try it with the lead ones just for completeness.

Really at loss here... It's not even like it's almost working. I tried single loading mag after mag and literally only 1 time out of 10 would it lock back.

[Bastard]

the 9mm 115gr is not listed in the Lyman cast book, but a quick google search and it seems that a lot of people are running the 115s on the lower side somewhere around 4.2/4.3

I haven't loaded lead in 9mm for a while, but I seem to recall using 4.5/4.6 of 231 but that was with a 125gr pill

[CEDaytonaRydr]

Not de-glocking. I was under the impression that's not needed with a Lone Wolf barrel since it has a fully supported chamber.

The opposite...

You need to de-glock because its a fully supported chamber. Once fired from a Lone Wolf, you do not need to de-glock again but you need to make sure the brass is at spec the first time you load it.

Of course, if you are using only your own brass, or new brass this is probably not the problem but I thought it was worth asking.

In general I didn't think it's necessary for 9mm at all, only ever heard of people doing it for 40 Cal.

If you were using a Glock barrel, probably not but in this case, maybe. Contrary to popular belief, 9mm cases do bulge, and the Lee de-bulger will work, if you use the 9mm Makarov FCD. http://leeprecision.com/bulge-buster-kit.html

[ElDub1950]

Lonewolf's notice states that because of the heavier barrel and slide 'some' guns experience problems with lighter rounds. Although those problems are more likely to be FTF/FTE. Try a box of 124 or 147gr to see if that's the right direction. LW also states that in some cases, running a couple hundred +P rounds will seat in a new barrel and you can go back to your normal loads.

http://www.lonewolfdist.com/Products.aspx?CAT=241

I run light loads in my G23 & G27 with the LW 40-9 conversions with no problems but there have been a couple other threads recently about cycling issues and heavier rounds helped.