G34 recoil problems

[Chapo]

Hello I am shooting a G34 with a 4-port comp. Today I shot several loads with autocomp from:4.8gr - 5.3gr. Recoil increased obviously as I increased the loads but all were stovepipes and few complete cycles. I was shooting with an 11lbs recoil spring and lee's 124 gr cast boolit powder coated. At this point what should I do? Clip the spring to a 10lb? Add more powder? Thanks

[kayala]

I'd be hesitant to add more powder. According to the hodgdon website you're already at the max of powder weight for FMJ bullet (5.2). Wolf has 10 lbs (https://www.gunsprings.com/GLOCK%20%C2%AE/cID1/mID5/dID116#109) springs for G34 which you might try instead of cutting existing one.

[Boolit_Head]

Which comp? You may have to increase the charge, most ipsc shooters running comped guns are probably using 115 grain and heavy charges to get the gun shooting flat at major levels. very possibly over maximum charge levels. Slapping a comp on requires a lot of tuning to get it to run right. a 4 port comp is a lot for minor loads.

I put a 3 port Carver comp and 11 pound spring on my G17 with the slide ride but have not gotten out to get it working yet. I already know I will have to run it in the +P load levels. Might want to check over on brianenos.com as there are lots of folks running comped glocks over there.

[Moonie]

On my sons conversion with compensated barrel he had to go to a gen3 light spring system as there was not a light spring available for his gen4 gun. It was offered by the same company that he got his barrel from.

147gr loads might help though.

[Chapo]

Thanks all. I am using a carver 4 port comp

[lefty o]

theres a world of difference between compensators, but as a rule, use slower burning powders and near max or max loads.

[Mytmousemalibu]

It took me quite a bit of tinkering on my Open Division M&P 9 to run right. I was shooting minor when I started with this gun and running a Carver 3 port comp. A decent comp will really take a lot of slide energy away. I'd bump down your recoil spring weight to a lighter one. You might have too much comp for the gun too. A hotter load may improve the functionality but gotta be careful. Lotta guys do run loads hotter than published maximums. I bumped up to major pf and my Silhouette load is above max but there are guys running more than even I do but in metal frame guns. I'm leery about it more so with polymer frames. You might look into trying out some Vhitavouri 3n38, you can make major with published data and at lower pressures. I was shooting a 3n38/147gr load that made major but my M&P just doesn't like 147gr bullets, accuracy isn't there. Im working on a 124gr load with that powder but have yet to test it so went back to my Silhouette load that performs very well albeit over max.

[Chapo]

I really like autocomp so far. It looks as of know that the solution could be cutting a bit the recoil spring. Maybe down to a 10.

[Boolit_Head]

With a 4 port comp you really have to be running hot loads.

[Chapo]

Also ordered a 10lb recoil spring and the Wolff competition pak. Any experiences with either of these?

[Mytmousemalibu]

With a 4 port comp you really have to be running hot loads.

I agree, i think you're probably best choice is dropping recoil spring weight and going to a 3 port comp. I know Carver suggests the 4 port for Major PF only.

[Boolit_Head]

From Carvers website. If you call them I've heard they are pretty good about getting you running.

Please note: 4 Port Compensators for use with 9MM are intended for "heavy" or "major" 9MM ammunition. Though they will work with some+P factory ammunition. Not all factory ammunition will allow for reliable functioning with this comp. A 3 Port Comp is recommended for light factory ammunition.

[Chapo]

This leads me to another question, Is a 124 gr Lee cast boolit over 5.3grs of autocomp considered light or heavy?
I am hoping that a 10lb spring will cycle the slide with the 5.3gr of autocomp. If not, I'll keep adjusting the spring down.

[Boolit_Head]

In terms of running a comp, light. From perusing brianenos.com forum ideal should be 115 grain with a lot more powder to produce a lot of gas to work the comp is what you want. I believe the loads they are using are over listed max.

[lefty o]

im currently running hs6 in mine, have a sjc 5 port and an 11 pound spring. 115gr plated with top end charge of hs6, runs like a timex. runs good on factory loads also though they dont get very far out of the ejection port. doesnt make too much sense to cut down on spring rate if your not running near a top end charge with a comp, you have to put as much gas as possible thru a comp for them to really work.

[Chapo]

Agreed. I believe I am in the max load range with 5.3 of autocomp and the 124 cast boolit.

[Mytmousemalibu]

Something else to consider, you may find you'll want to switch away from a cast bullet in a comp'd race gun. I wanted to run my own 124gr TC's through mine when I started my Open gun fun. I found out really fast that even with powder coated bullets, the blast through the ports of the compensator as the bullet passes through was gas cutting the bullet bases and depositing quite a bit of lead in the comp. A good friend of mine that shoots Open was getting a leaded up comp with open-base FMJ bullets. I have switched to Plated only in the open guns. It's cause for more airborne lead for us to deal with. I really like Berry's 124gr hollow base RN thick plate bullets. The heavier plating holds up better to hot Major PF loads and it is my suspicion that the hollow base obturates very well to the barrel under these hot loads. Just some food for thought.

[Chapo]

Great food for thought!!

[Chapo]

With the 4 port comp i have, if/ when I add more powder the recoil will be hard with the 11lb spring. I guess I'll have to add powder and change to a 10lb spring?

[Mytmousemalibu]

You could try one or the other by itself. I would probably probably load a ladder charge of test rounds to try and also take your recoil springs to the range and do some testing. Not only for functionality of the gun working right but also for accuracy and muzzle control. Seeing how well the comp is holding the muzzle flat.

Open guns are fickle creatures and getting them to run right can be an exercise in ones patients at times! The open gun motto, take a perfectly good working gun and fix it till its broken, then make it work again!

[Boolit_Head]

Open guns have to be tuned to the load. You find a load you want to run then get the gun to run it by changing comps or recoil spring rates to get the gun to shoot flat. If you change the load you have to do it all over again.

In this case for the load there is to much comp, in that situation it will be very hard to get it to run at all. Up the powder charge to +P levels before you try to adjust the recoil spring rate or you will find the slide coming back to fast and a host of other problems.

[Boolit_Head]

Come to think of it some of the open 2011 38 super guns are probably running in the 7 to 8 pound range with much hotter loads.

[Chapo]

Thanks all. Appreciate all he feedback. Made a ladder of test loads ranging from 6-7.4grs and bought a 10lbs spring a kit with other internal trigger springs. Will post results....

[Chapo]

Well, went to the range and had catastrophic results. I started with the 11lbs spring, 5.7gr of auto comp and the cast 124gr boolit. Also installed the competition trigger spring kit. The OAL was 1.065. From 5.7-6.6gr all cases were showing signs of pressure, although I did not notice. By 6.7grs the explosion occurred. The force expelled the mag and gave me a big scare. Me, being stupid, had to confirm, and replicated the issue by firing a second round and the same happened. This time, not only the mag was expelled, but the magazine release busted out and broke in two.

This pic is the incremental signs of pressure....
176017
View of primers...

176018

Busted mag...

176019

Next, I will replace the part, change the recoil spring to a 10lbs and will probably create loads in the 5-5.6gr range. Then shoot again.

Thoughts?

I figure, other people shoot much more hotter loads from g34; I'm just wondering what Im doing wrong.

[Boolit_Head]

Did you go look on Brian Enos? Several of them are probably running lighter bullets and probably using different primers. Read with caution because some of these are highly tuned 2011's and may be loaded longer than your glock. But these are the people who are running those loads all day.

http://forums.brianenos.com/index.php?/topic/235420-autocomp-9mm-major-load-data/#comment-2625301

[Chapo]

Yeah. Great source. Maybe I should try the small rifle primers.

[Mytmousemalibu]

Oh wow! Yikes! Unless you made a typo, that OAL is wayyyyy too short. In fact with a 124gr boolit with that big of a charge of Autocomp, that's gotta be getting into compressed load territory with OAL that short. I would not be at all surprised if that was the cause. I know larger charges of Autocomp have been burned off in 9mm's without case ruptures. Also, is your 124gr boolit of proper size per slugging the barrel?
My 147gr load had me seating all the way out to 1.180 and I can seat all the way out to 1.200 in my M&P. You won't have that kind of room in a Glock because of the thickness of the mags will probably limit your OAL before your chamber will.

[Chapo]

Thanks Chris. Will increase OAL.

[Mytmousemalibu]

Yeah, seating that short will send your chamber pressures through the roof. I just looked at your primer pictures and there is some very defined flattening of the primers in the ones in the right of the picture and heavy cratering with the primer cup flowing into the rectangular firing pin hole. It's pretty common for 9mm Major loads to exhibit some signs of pressure. My primers are flattened somewhat and I do get some cup flow into my firing pin hole but it's not to an extreme degree like some in the right of your picture. I would load up a dummy round, just a piece of sized brass and seat a bullet in it way long, like say 1.220 should do. Little by little, seat the bullet deeper and deeper checking it in your mags to see when it will fit and freely travel in the mag with out dragging the bullet and wedging in the mag body. Too long/not enough clearance will result in feeding issues. When you establish a maximum magazine OAL, see if that will chamber in barrel fully. You may find the ogive on that cast 124gr'er and the throat length of your barrel don't mesh. That is a pro to the 124gr plated RN bullets, the ogive they often have allow for seating long. The throat measurement will vary with each bullet design too so keep track of that. There is a fine balance between OAL, charge weight, powder type, bullet, etc. It can be tricky finding this balance. Adding in the issue of tuning the load to work the comp, run the gun and maintain accuracy, etc, etc is another story. You might have to go with another powder besides Autocomp to get where you need to go. I would certainly pick brains of the gang at Brian Enos to get your loading back on track. That might save you a lot of headache trying to fully tune a load from scratch and just have to do a little fine tuning. Those case head ruptures are no joke, that's an easy way to get hurt. A good friend of mine had an XDm 9mm open gun that had a case head rupture but instead of blowing the mag out, it popped the frame on the right side and beat his hand up a little bit. Lucky judging on what the optic mount looked like. Be careful, gotta be on your tippy toes with 9mm having to be as hot as it does in some of these race guns.

[Chapo]

Thanks again. I played a bit with the OAL and from the longest, it started chambering at 1.085". So I loaded a few of these from 5.7 to 6.4gr and also changed the recoil spring to 10lbs. We'll see what happens tomorrow. Chamber pressure should be less.

[Chapo]

Went to the range again and tested those loads although I only shot 5.7-6.0grs. Noticed the sweet spot is 5.9grs with the 13lbs recoil spring. No issues afterwards.

[Mytmousemalibu]

Glad to hear you are getting it sorted out!