G17 misfeeds

[kevin c]

G17 with 15# uncut ISMI spring on the std guiderod (the slide moves out of battery on a hard reload with anything lighter). New magazines with std. followers (2183-1). 147 gr MG CMJ's loaded to 131 pf at 1.150.

I'm getting misfeeds where the round noses up into the chamber, but the stripper rail isn't on the base of the round, but up on the extractor groove. It's happening with multiple mags, regardless of grip. Is this the slide short-stroking, and if so, why?

Is the spring too heavy? Instead of going to a 13# (which had the out of battery slide mvt on reloading), should I cut a coil or two off the 15#?

Is it possibly the mags? They're new, w/ new springs and followers.

Is it the ammo? do I need to alter the OAL, or up the PF?

TIA,

Kevin

[HSMITH]

That is called a 'bolt over base' malfunction, and it is a result of the slide stroke either being short or stroking faster than the magazine can keep up. With the pooch of a load you are shooting I would be pretty comfortable telling you that your slide isn't outrunning the magazines. Bump that load up to about 140 PF, it will complete the stroke and the gun will run again.

[mscott]

You could try a lighter spring, but my guess is ammo. That load sounds a bit long to me (I try to keep mine under 1.135). I also run a 13# spring for minor loads.

[psyops]

Kevin,

After checking your ammo, look at your mags. Are the springs working o.k.? I had this problem in my open 9mm major big stick gun, and I replaced the mag springs and amazingly all is fine. For me, ISMI mag springs work good. Just a thought...

[Flexmoney]

First round out of the mags?

- Glock 10 round mags usually suck with 10 in them. Downloaded, they work better. (I've never looked into tweaking on a 10 rounder to get a pinch more room in there, but I would if I lived in Cali.)

- ISMI recoil springs can bind, limiting slide travel.

- Those 147's at 1.150 may be a bit long. I'd suggest going down to 1.135 - 1.140.

- A little bump in power wouldn't hurt things.

- Make sure you extractor and spring (load bearing or whatever it's technically called) is properly installed.

[kevin c]

Thank you for your comments, folks.

Living in the not so great state of California, 10 rd mags are all I can play with for my Glocks, but downloading a tenner to a niner isn't too palatable in the games I use them for, and is outright illegal in one of them. (Production and SSP). If I want to shoot fewer rounds, well, Hopalong just sold me a Single Stack, so that's what and where I'll play the ammo management game. It's not necessarily the first round out of the mag anyway.

I'll try shortening up the round. Three possible pluses there: shorter OAL to change feeding, a little bump in pressure/velocity/PF, and the fact that, if it is the ammo after all, if it works, it saves me the 1700 rounds I've loaded already, thinking I had the load dialed in (didn't I just post something about prematurely committing to a load? )

I'll read up on Matt's suggestions on coil cutting the springs, if the ammo tweaking doesn't do what I need.

And here I thought I was ready for the California Cup (state IDPA championship) next week

Edited June 24, 2007 by kevin c

[RePete]

First round out of the mags?

- Glock 10 round mags usually suck with 10 in them. Downloaded, they work better. (I've never looked into tweaking on a 10 rounder to get a pinch more room in there, but I would if I lived in Cali.)

- ISMI recoil springs can bind, limiting slide travel.

- Those 147's at 1.150 may be a bit long. I'd suggest going down to 1.135 - 1.140.

- A little bump in power wouldn't hurt things.

- Make sure you extractor and spring (load bearing or whatever it's technically called) is properly installed.

I'm using the 10 rounders and have not had a problem. I got the 17 a week ago.

My load is 3.9gr Unique under a 147gr Frontier RN, for an OAL of 1.120", and they feed beautifully.

[sgtis108]

I just bought my girlfreind a 34 and she is having the same malfunctions. Funny when I pick up the gun it runs like a sewing machine.

It is still stock. I put a 13# spring from my 34 in it, No help. I gave her a 17 with 100k through it and it runs perfect. I finally loaded her a mag full of 140pf factory ammo and it ran fine. My loads are at about 133pf.

My conclusion is that the combo of her wrist plus the new(tight) 34, plus the light rerload is causing it to short stroke. Keep in mind that it runs fine when it shoot it.

SGT

[Flexmoney]

It's not necessarily the first round out of the mag anyway.

That puts me back to recoil spring bind.

[SA Friday]

first try shortening your round and then make sure the crimp is correct. I would always recommend a Lee FCD. I had some problems with my Glock 24 because I was leaving just enough of an edge on the brass after crimping that it would hang up in the throat and cause a miss-feed. These should both be easy to beta test before starting any testing that will cost.

This is the second thing I would check. You may be having problems getting your 34 to lock up with a 13lb ISMI spring if you did not go to a reduced striker spring. That light of a load (130pf), I wouldn't be at all suprised if you are not getting a full stroke out of your slide during the firing sequence. It took a 13lb spring with 3 coils cut off to get a good ejection on my 130pf 147gr zero loads. If this is the case, Your choices are going up in PF on your loads or respringing the gun. 1 Wolfe Competition Spring pack, and one 13 lb ISMI spring, 30 minutes changing the springs, and maybe a set of good cutters during testing.

[Fireglock]

It's not necessarily the first round out of the mag anyway.

That puts me back to recoil spring bind.

+1 on the recoil spring bind, it happens with ISMI springs. If you cut the spring it may well go away, I just went back to Wolff springs.

[Nik Habicht]

First round out of the mags?

- Glock 10 round mags usually suck with 10 in them. Downloaded, they work better. (I've never looked into tweaking on a 10 rounder to get a pinch more room in there, but I would if I lived in Cali.)

Far be it from me to argue with Flex, but that hasn't been my experience in 9mm --- and I've been shooting the ten rounders in production exclusively since 2002. Unlike .40 and .45 ten rounders, the 9mm mags actually have some flex left after loading ten rounds......

- ISMI recoil springs can bind, limiting slide travel.

I've seen/experienced that as well, and now use Wolff 14 lb. springs with nary a hint of trouble.

- Those 147's at 1.150 may be a bit long. I'd suggest going down to 1.135 - 1.140.

- A little bump in power wouldn't hurt things.

I'd say 1.150 is way long, especially considering the shape of the CMJs. I load that bullet to 1.100. You may need to reduce your powder charge/re-chrono, if you decide to shorten that far, but you should pick up a little bit of velocity too. My loads with Titegroup chrono between 131 and 132, and the guns, from 34s to 26s with stock recoil springs run.

[elenius]

I shoot a G22 with 10-round mags, and they just would not go in without extreme physical violence, unless the slide was back. I kept the mags loaded to ease up the springs, but it did not help.

The solution was to cut off one coil on the mag springs. Everything is now working perfectly. I have run the gun like this for thousands of rounds without a single problem.

I use a 13# recoil spring on a steel guiderod, and 128PF loads.

[kevin c]

Update:

Cut three coils off the 15# ISMI spring - no difference. (I had checked for spring bind before hand by noting the full rearward travel of the slide/bbl w/o the spring and guide rod compared to with them in the gun. Each has the same travel, but I thought I'd try the shorter spring anyway).

Also shortened up the round from 1.150 to 1.135 and 1.125. Some improvement with the 1.135's, but still with misfeeds. None, though, with the 1.125's in combination with the shortened spring (didn't have time/enough ammo to check with the stock length spring).

So shorter is better. Will recheck with more ammo and the stock spring.

Thanks for your suggestions.

KC

[HSMITH]

Shorter = higher pressure, more velocity and more recoil. Bump the charge a little and be done with it.

[kevin c]

Shorter = higher pressure, more velocity and more recoil. Bump the charge a little and be done with it.

That I will, but for now, being short on components and with 1700 rounds already loaded and a major just a weekend away, I'll do what I can with what I have.

Reworking the load more (bumped charge, +/- an OAL change) will have to wait just a bit.

Thanks all.

[Joe D]

There is something odd going on with your gun. Wish I could get my hands on it. My Glocks feed everything I stick in them. I have used springs as light as 9 lbs and bullets as heavy as 160 gr with an OAL of 1.160". I run my G35 at a 135-136 PF. It will easily function at 128, but the occasional stiff piece of brass will not expand enough to seal the chamber at that PF. My current 9mm load is a 160 gr RN at a little over 800 fps. I use a 12# Wolf spring for everything - Major or Minor.

It is starting to sound like a bullet profile issue to me. One of my shooting buds went in with me on a large purchase of 180 gr. Precision Delta bullets. He had feed issues from day one with these bullets. My two G35s have not missed a beat with them. I wound up buy his share of the order.

[Nik Habicht]

Kevin

I suspect Joe is right --- it's the profile of the bullet you're using. I also continue to think that 1.125 is still too long.....

[HK Dan]

I've had the same problem--bump the load and be done with it.

It's not the profile of the round, it's not the recoil spring, and it's not the OAL. You don't have enough 'bang' in there. I load 4.9 grains of Bullseye under a 115 grain Rainier RN at 1.130". I agree that 1.150 is too long (even with a 147), but it's not causing this problem. The gun isn't wierd, and the problem is common--I agree with the consensus on the post. The slide is short stroking (not getting the spent case to the ejector) because it doesn't have enough power. It's close! But not enough.

It's not a real advantage to shoot powder puff rounds in a 9mm anyway--quit trying to game it and just load 'em like you want to put some holes in something solid.

HK Dan

[HSMITH]

Agree with Dan. Bolt over base malfunctions are not bullet profile related, not even a little bit.

[sgtis108]

I found the fix to my problem. I noticed that my girlfreind was letting her weak thumb rub the slide.

Just enough to take some of the velocity from the slide and make it short stroke.

Check your thumb to slide fit.

Just a thought.

SGT

[Fireglock]

I live at minor power factor and my Stock gun 17 with stock recoil spring runs either Xtreme 135gr RNFP or Zero 147 JHPs over 3.5 of Rex #2 all day long. All my ammo has been loaded at 1.150, it works fine. I still run the same load in my 17L w/12lbs spring and it flies along fine. If the trouble isn't spring bind then magic thumb or weak mag springs where the mag not keeping up with the pistol would be my next steps.

[Flexmoney]

If none of that...then start looking for major failures....cracks in the slide...frame rails...etc.

[BayouSlide]

I use six 10 rounders as practice mags and have 18 hi-caps reserved for competition (USPSA Production). Never seen this type of failure from the hi-caps. But despite new mag springs and updated followers from Glock, three of these 10 round mags still consistently exhibit this type of failure, especially if my G34 has gone a couple of sessions (300 - 500 rds) without cleaning.

I use ISMI 13# springs and loads at about a 134 PF...the 10 rounders at their best just don't seem work as well as the standard hi-caps, all things being equal, in my experience. Some seem to work better than others, for some reason.

Next time I've got a few spare bucks and run into a good deal on standard mags, I'm canning all six 10-rounders.

I feel your pain, bro, and sorry that isn't an option for you because of your location.

[kevin c]

My 17, as best I can tell, is mechanically sound.

I'm thinking now that HSmith is on the money. I had several more failures with the shortened ammo at last week's match, and realized that they happened a lot on SHO/WHO shots, and some free style shots off the draw where I got a sloppy grip.

I had tested a lot of rounds, both in the original load work up and in trying to tweak it afterwards, but they all went over the chrono, into the berms or into the targets during drills where I shot freestyle only and had time to set up my grip and stance well. I'm not a big guy with an iron grip, and I've been known to get sloppy acquiring my firing grip on the draw. I've been too busy to shoot the practice stages our club usually sets up, so a match conditions shooting test didn't happen.

I also remember that, preparatory to this weekend's IDPA match, I swapped out the THE tungsten guide rod for the stock plastic version. The original load had been worked up the the THE rod in the gun, which tended to stay down in recoil just a bit better than with the OEM rod. It's also possible that sometimes using my tuned G35 lower with the G17 upper adds to the problem (though I don't see how right now).

So basically now I'm thinking the ammo is marginal PF wise, given the change in the gun and shooting circumstances that that let the muzzle rise earlier in slide travel and kill the rearward slide mvt just enough to cause the bolt over base malf.

Ammo testing, I now realize, really needs to duplicate match conditions, both equipment and technique wise.

Back to my 140-145 PF G35 load for this weekend (glad I have enough lying around to get me through the match).

Lesson learned (hopefully).

Edited July 5, 2007 by kevin c