Glock 34 Double Diamond Barrel OAL issue?

[thelaserman]

Hey Folks, not sure if this should be here or the glock section. Long story short, I had a out of battery discharge on my Glock 34 gen 3 last week.  Gun mostly survived, except the trigger and mag release broke, and my extractor shot out and was lost.  I had a local shop check it out, and everything looks straight.  I figured i would replace the barrel as it takes the brunt of the force (it looks fine) just to be on the safe side. 

 

I ordered a Double diamond barrel from the glock store and it arrived today.  I grabbed a few of my reloads and tried to plunk test them, and they all failed.  I have 2 loads and they both failed.  

1: 125g RN Blue bullets 3.5 TG with OAL of 1.125

2: 127g RN Blue Bullets  3.1 TG with OAL of 1.135

 

using my Hornady LNL AP i do get some variance, but non of the rounds were over 1.142   and I have a few thousand of each so i would prefer to not have to break them all down. 

 

Neither of these fit. I grabbed the press and worked out the Max oal to be 1.120.  That seams pretty short as the max allowable, and given human and mechanical variations, i assume i would have to load to a max of 1.175 or so

 

I chatted with GS but they were unsure of the max OAL for that barrel and offerered to send me a replacement to see if that's any better.   Has anyone else had this issue?  Is this and issue? I am hoping the replacement barrel accepts my reloads. If it doesn't do you have any suggestions, can i load that short? How much would i have to adjust my load. 

 

Thank you for the help

 

[bowenbuilt]

Send me the barrel with a few dummy rounds and i can adjust the leade so you don't have to do anything. I don't charge forum members for this service. PM me and i will supply an address and will do a one day turn around for you.

[thelaserman]

Thanks so much, that's an amazing offer. I just dropped the barrel back in the mail to GS, when I get the replacement if there are issues, I will certainly take you up on the offer.

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[IDescribe]

9 hours ago, thelaserman said:

That seems pretty short as the max allowable, and given human and mechanical variations, i assume i would have to load to a max of 1.175 or so

 

If it doesn't do you have any suggestions, can i load that short? How much would i have to adjust my load?

 

 

(1) I assume you mean 147gr and not 127gr for that second load?

 

(2) It is valuable to know where you went wrong.  One thing I would do is determine the true max OAL on the barrel you are replacing.  If you had an OOB, you were problably very close to the max on average anyway.  Load a dummy round (size, bell, seat, crimp) to 1.150, plunk and spin test in the pulled barrel, then start shortening .003 at a time until it spins freely.

(3) An LnL should not be producing that much OAL variation.  Have you modified it?  Did you shim/washer the shellplate to tighten things up?  If so, remove it.

(3) Seems short?  Compared to what?   There is NOTHING short about 1.12.  

(4) Standard procedure when shortening OAL on a known load is to re-run load development, start at starting load, and work back up.  In practice, shortening .02 with TG is going to be worth about a tenth of a grain of powder, and your load looks super light to begin with.  Not even sure that 125gr load would make power factor.  With the Blue 125gr at 1.100 OAL, I am showing an average velocity of 1018 with 3.6gr of TG, which was my STARTING load in load development.  I would not expect 3.5gr at 1.125 to make power factor, or if so, by just a hair.  I shot that bullet with 3.9gr of TG for an average of 1076.

[thelaserman]

sorry about my fat fingers typing...  

8 hours ago, IDescribe said:

 

(1) I assume you mean 147gr and not 127gr for that second load?

 

(2) It is valuable to know where you went wrong.  One thing I would do is determine the true max OAL on the barrel you are replacing.  If you had an OOB, you were problably very close to the max on average anyway.  Load a dummy round (size, bell, seat, crimp) to 1.150, plunk and spin test in the pulled barrel, then start shortening .003 at a time until it spins freely.

(3) An LnL should not be producing that much OAL variation.  Have you modified it?  Did you shim/washer the shellplate to tighten things up?  If so, remove it.

(3) Seems short?  Compared to what?   There is NOTHING short about 1.12.  

(4) Standard procedure when shortening OAL on a known load is to re-run load development, start at starting load, and work back up.  In practice, shortening .02 with TG is going to be worth about a tenth of a grain of powder, and your load looks super light to begin with.  Not even sure that 125gr load would make power factor.  With the Blue 125gr at 1.100 OAL, I am showing an average velocity of 1018 with 3.6gr of TG, which was my STARTING load in load development.  I would not expect 3.5gr at 1.125 to make power factor, or if so, by just a hair.  I shot that bullet with 3.9gr of TG for an average of 1076.

sorry about my fat fingers typing.  Yes you are correct and i meant 147gr.  Also my load for the 125gr is 3.7, not 3.5....   These worked out to be 133 PF  average and the 147s at 3.1 avg 131pf.   

 

My plate is not shimmed, i do have a split washer on top and under the shellplate nut like most folks recommend.  I definitely get some variation in OAL.   In the stock glock barrel i created a dummy round at 1.155 and it plunked and spun fine, so i was nowhere near max OAL with my 1.14.    

 

I am guessing my best option is to take bowenbuilt up on his offer, and send him some dummy rounds  so he can ream the chamber for my existing ammo.  

 

Thanks

 

[iflyskyhigh]

Send me the barrel with a few dummy rounds and i can adjust the leade so you don't have to do anything. I don't charge forum members for this service. PM me and i will supply an address and will do a one day turn around for you.

Which reamer do you use sir? I’m looking to add one to my kit.


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[bowenbuilt]

I use a Dave Manson reamer. You can purchase one from Dave for about what one rental costs. I belive i paid $40.00 for the last one I purchased from him last year. He will also resharpen them for you.

[iflyskyhigh]

I use a Dave Manson reamer. You can purchase one from Dave for about what one rental costs. I belive i paid $40.00 for the last one I purchased from him last year. He will also resharpen them for you.

Good deal. That’s the one I was looking at in his online catalog thanks for the input.


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[IDescribe]

16 hours ago, thelaserman said:

 

My plate is not shimmed, i do have a split washer on top and under the shellplate nut like most folks recommend.

 

Yeah, most folks recommend you do what they do, and all they did was what someone else told them to. 

Okay, so many years ago, a handy fella at ar15.com was unhappy with his Dillon 650 OAL consistency and went through a lot of analysis and conversations with techs at Dillon and figured out a way to secure the shellplate on a 650 to improve OAL.  This involved a wide washer or two below the shellplate to tighten things up and make it more stable.   He did some other stuff, too, but the washer was 95% of the improvement. It's a good modification to make -- to a 650.  Now there are videos all of the internet of people recommending the same thing with a Hornady LnL, but the LnL is not the same design.

 

I no longer have an LnL (long, tragic story), so I can't duplicate what you have done to assess it specifically in this moment.  I see no problem with a split washer on top of the shellplate.  HOWEVER, do not put anything below the shellplate. 

 

On a Dillon 650, the case rims are held by the shellplate, and when it is driven into the dies,  the shellplate receives that force, and flexes and tilts JUST a little, a hair. 

 

But this is not the case with an LnL.  On an LnL, the cases aren't supported by the shellplate.  The cases are supported by that thick heavy subplate when the cases are driving into the dies.  All the shell plate does is slip into the extractor groove, then slide the cases around on the subplate to their next stations.  If you raise that shellplate at all, the shellplate can partially support the cases from the extractor groove instead of the subplate, and OAL consistency (and runout) will suffer.

At the end of the day, because the cases are support by the subplate, nothing you can do to the shellplate can make things better, only neutral or worse.

When I had my LnL, I had that bolt holding the shellplate back out on me a couple of times.  I eventually found the right tension to hold it in place.  If I remember correctly, it would back out to where it would want to be, then I would check it and think "oh, it's loose," and I'd snug it back down, only to find it "loose" again later.  And I ultimately figured out that if I left it alone, it was fine.   

[olstyn]

On 11/28/2018 at 6:08 AM, IDescribe said:

(3) Seems short?  Compared to what?   There is NOTHING short about 1.12.

 

^ This. My standard load for quite a while was a MG 124 JHP @ 1.075" - that was as long as they'd reliably plunk in my Walther P99 and P99c's barrels.  1.12 sounds almost luxuriously long to me.

 

Of course, it's easy to understand the OP not wanting to disassemble thousands of rounds, so I guess either reaming or using the old barrel is probably the answer.  Given that in an OOB detonation, the pressure gets "vented" wherever the barrel isn't supporting the brass, it probably receives considerably less mechanical stress in an OOB detonation than it does in normal firing.  I'd be pretty surprised if it wasn't completely usable.

[MemphisMechanic]

On 11/28/2018 at 7:50 PM, iflyskyhigh said:

Good deal. That’s the one I was looking at in his online catalog thanks for the input.

 

 

A manson in a Glock barrel?

 

Good luck. They’re high speed seel. The barrel chews them down like crazy; you’ll ruin it in one use. Ask me exactly how I know.

 

HSS is great for CZ/Tanfo/1911 barrels. Not for guns with hardened ones.

 

I have a carbide one now which cuts hardened Glock/M&P/Walther barrels like butter. You need carbide. Happy to cut yours on the cheap if you’d like.

 

But a HSS reamer isn’t the right tool for the job. Don’t wsnt you to waste $50 like I did.

[bowenbuilt]

That is correct. Manson does not make a reamer for the OEM Glock barrels. They are way too hard for the standard reamer. Most of the aftermarket barrels will work but not the super hard OEM Glock barrels. That is also true for the Springfield XD/XDM or the new CZ Shadow 2 barrels or any Nitride/Melonite coated barrels. You will need either a carbide or a diamond coated reamer for these.

[IDescribe]

The P09/P07 are so hardened.  Probably the P10 barrel, as well. 

[MemphisMechanic]

2 hours ago, bowenbuilt said:

That is correct. Manson does not make a reamer for the OEM Glock barrels.

 

If you need one cut, I can do it, though. Don’t mind helping guys out.

[bowenbuilt]

Laserman,

Your barrel is done. I received it today and will have back out to you on Monday.  No problem reaming the Double Diamond at all.

[thelaserman]

Thanks man

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[bowenbuilt]

2 hours ago, MemphisMechanic said:

 

If you need one cut, I can do it, though. Don’t mind helping guys out.

This is good to know. Thanks!

[iflyskyhigh]

 
A manson in a Glock barrel?
 
Good luck. They’re high speed seel. The barrel chews them down like crazy; you’ll ruin it in one use. Ask me exactly how I know.
 
HSS is great for CZ/Tanfo/1911 barrels. Not for guns with hardened ones.
 
I have a carbide one now which cuts hardened Glock/M&P/Walther barrels like butter. You need carbide. Happy to cut yours on the cheap if you’d like.
 
But a HSS reamer isn’t the right tool for the job. Don’t wsnt you to waste $50 like I did.

It’s not for factory barrels. All after market barrels being reamed. I used a buddies to do one of my barrels already so I know it works. Good to know reference the factory barrels. Thanks for the info.

Which reamer do you use for the factory barrels just out of curiosity?


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[MemphisMechanic]

I got it from 1911luvr here on the forums, his machinist makes them in carbide. Had to turn .001” off the pilot with a diamond lap in order to get it to fit into polygonally rifled barrels, and now it works great!