Intermittent premature slide lock with K9 & TP9

[oldtex]

All,

I'm experiencing infrequent premature slide lock with both a K9 and a TP9, both bought new within the last two months.

The K9 has a total of 791 rds through it, using four different mags (three 7 round and one 8 rd mag). Ammunition was a variety of Federal 115 gr FMJ, PMC 115 FMJ, Blazer Brass 115 FMJ, Winchester USA (white box) 115 FMJ, and 220 rds of Federal 147 gr HST (P9HST2). Have cleaned and lubed (with FP10)the gun approx. 6 times throughout this period.

Have experienced one horizontal stovepipe at about rd 750 or so using Winchester white box, using the 8 rd mag, shooting with both hands in a thumbs forward grip and modern iso stance. Replaced the OEM rubber stocks with OEM wooden stocks prior to this shooting session.

Also experienced one premature slide lock at about rd 600 using the P9HST2, shooting strong hand only, thumb forward grip, using the 8 rd magazine, second or third rd into the magazine.

While clearing the gun after the last shooting session, I noticed that slide resistance seemed weaker than when new, and that when empty the gun didnn't go into battery as vigorously as when new, so I replaced the recoil spring with a new Wolff standard power 20 lb spring. With the new spring, the gun goes back into battery with its old vigor.

The TP9 has 543 rds through it, a combination of 343 Federal and Win 115 FMJ and 200 rds of Federal 147 gr HST (P9HST2), using its four 8 rd mags. Have cleaned and lubed five times. Only malfunction was a premature slide lock, at about the 500 rd mark, shooting weak hand only, using the P9HST2.. Added a Crimson Trace LG-437 laser to the gun at about the 343 rd mark.

I believe that the K9 stovepipe may have been caused partially by a weakening recoil spring. It does seem odd for a recoil spring to go south after less than 1k rds, but like I said above, it did feel noticeably weaker when racking the slide, and didn't pop back into battery with as much vigor as when new (even with no rds in the gun and no mag either). And Kahr CS recommends changing recoil springs at a 1k-1500 rd interval.

I am tempted to blame the premature slide locks in both guns on my grip. My hands are meaty and I typically shoot all autos with a thumbs forward high grip. I have read an article on Kahr's website where the author opined that his weakhand premature slide lock with a .45 Kahr was caused by his trigger finger contacting the slide stop.

This morning I pulled both guns out, removed the slide assemblies, reinstalled the slide stops, and seated several different loaded mags into the respective mag wells. I only used the P9HST2 as this was the ammo in both guns when they experienced the premature slide lock. I was looking for contact between bullet noses and the slide stops. There was clearly none if the rds were carefully seated all the way to the back of the mag. If the rds were not carefully seated all the way to the back of the mag, I noticed that the nose of the bullet (especially the round below the top rd)came awfully close to the slide stop, but I couldn't see any actual contact.

I closely examined the profile of a P9HST2 rd and a Win USA 115 gr FMJ rd. The nose of the P9HST2 rd was noticeably wider than the 115 FMJ rd. This could be a contributing cause as well.

Any thoughts?

[wyntrout]

Your grip is a big factor. The K9 problem was likely mainly because of the weakened spring.

I have a K9 and a PM9, but I'm not familiar with the TP9. I would say that shooting weak hand there was the problem. These guns require firm grips so that the recoil can cycle the action properly. Some require even firmer grips.

From day one(March 5th) up until the third trip to Kahr where the replacement slide with bad engraving was replaced with a beautiful one, I could hold the PM45 loosely and let the recoil make the gun rise... kind of giving it its head.

Since the NEW replacement slide, I have to really concentrate and have a "machine-rest-type" grip. If I let up at all, I get a stove pipe. I USED to get those when I tried a weak side two-handed grip. I tried one shot with my right hand and tried to really hold it firmly... stove pipe. One-handed shooting or weak side with it is out of the question, which makes its use for CCW problematic.

Kahr got the PM45 last Friday (20th) and I haven't heard anything on the magazine failures suddenly happening all at once. I don't know what will become of this problem. I'll have to wait and see what I have to do in the way of breaking in the new parts or new gun.

I don't think you have a real problem now. Just concentrate on your grip and realize that you might have more problems single-handed or weak hand shooting. Some of these guns are more forgiving with your grip.

Wynn:)

[OldLincoln]

On .45, the HST is longer than some other rounds and the taper comes later. I suspect the same for 9mm. The late taper puts it very close to the slide lock lug and in my 1911 would knock it up enough to lock periodically. I had FTFeed when it nosed into the ramp and stuck.

On my PM9, it started out not feeding well but I loosened the right mag lip and that issue went away. I did not have the slide lock problem.

It you can do it safely, watch the action when slow feeding a round and note how close it comes to the slide lock lug. Some have trimmed a tad off the lug in conjunction with making sure the mag follower still hits it.

HST is awesome ammo, but only if it feeds, shoots and ejects reliably.

[ripley16]

My first thought is that 1 stovepipe and two premature lock-backs between two guns with over 1300 rounds isn't too bad, especially when the most logical reason for two of the problems is an errant finger or thumb.

Your ammo is pretty good quality, the lowest power maybe the WWB, so I doubt an underpowered round was the cause. It sounds like the stovepipe problem may have been spring related, which you've solved, but stovepipes are caused by a number of reasons, so only time will tell. Cleaned and lubed properly, the K9 should prove to be an extremely reliably pistol.

I've had one lock-back with my TP9 since I've had it, and don't know for sure, but I assume I caused it because I haven't seen one since.

[jocko]

I would think that if it was ammo related it would do it alot, or if it was part failure, it would do it alot. Being you only had a few out of thousands of rounds and you think your thumb might be the issue. just be more aware of your shooting position and grip .