Glock 34 Accuracy Problems

[rpm8300]

Experts - please let me know what you think.  I'm setting up a Glock 34 MOS for carry optics and I've had issues with accuracy and 147s.

First round of tests - G34 MOS with OEM barrel, Deltapoint Pro, 20 yards

-147 Blue Bullets RN, 2.8 VV310, Fed SPP, 1.13 OAL - 5" group with occasional fliers outside of the 5".  For reference, this round just chrony'd at 890 fps.

-Same result with 147 SNS.

-147 Plated are even worse accuracy wise. 

 -I tried 124 PD JHP with some Autocomp that I had lying around and loaded to power factor, it was very accurate, 2" groups

Second round of tests - same gun but with a brand new KKM barrel:

-All of the 147 loads pretty much shot the same

-The 124 PD JHP is even more accurate - as accurate as my open gun shooting 1.5" groups consistently

 

This has been extremely frustrating because the exact same 147 Blue bullet load is very accurate out of my 1911 9mm.  That gets 2" groups easily. 

 

I've checked the crimp and tried different OALs.  I figured the OEM barrel wasn't well suited to shoot the moly bullets accurately, but when the KKM shot the same, it was disappointing.

I'm going to load some 147 Blue and SNS bullets with autocomp and 700x to see if its the lighter powder loads of the VV310.  I have a suspicion that the rounds aren't going fast enough. 

[wtturn]

All my glocks shoot 124 markedly better than 147. I switched exclusively to 124.

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[36873687]

I have noticed my glocks like 138 pf or better shooting 147 blue or bayou. 

[MemphisMechanic]

As the others said, try loading them hot before anything else.

I've run into several guns that wouldn't shoot 147s accurately until they were quite a bit hotter than you'd want to shoot them in USPSA or IDPA.

It sucks, because you bought them to shoot marshmallow-soft ammo in matches and it probably means you'll have to shoot them through other guns, but at least you have an answer.

[9x45]

I have to run coated 147s them to the Major floor before they start to tighten up. And no plated bullet groups good out of my Glocks, OEM or BarStos.

[36873687]

Idk if it would help but maybe kkm barrel

[rpm8300]

Thanks fellas - I have a KKM and it didnt help with the close to PF 147 loads.
I'm trying Autocomp instead of VV310 and I'll post results.  Thanks,

Tom

[rooster]

I have the same problem.  I can't get my 34 to group less than about 3  inches at 25 no matter what I do.  I have tried a semi fit Barstow, KKM, and I just bought a S3F, haven't tried it yet on long stuff.  I even bought a frame.  I have tried numerous powders and bullet weights.  The match barrels are not that much better than stock.  I'm pretty much just going to live with it at this point.  

[olemiss]

You might try a Barsto gunsmith fit barrel.  I put one into a G34 and a G19, and they both shoot as well or better than any of my custom 1911's.  Plus, the gunsmith only charged me $90 to fit the barrel as opposed to $300 to fit a 1911 barrel.  I tried various semi fit barrels, and they did not do much better than stock, but they did shoot a variety of ammo the same with decent groups.  The stock barrel shot some ammo with good groups and some ammo bad groups.  I got Doug Jones at Acc-u-rail to do the barrel fitting.

[IDescribe]

You do NOT need an aftermarket barrel.  The stock Glock barrels will produce 2-inch groups at 25 yards all day.  What you NEED is to load for accuracy instead of recoil.  A Blue Bullets 147 loaded to a PF of 131 with N310 is pretty much a perfect recipe for soft recoil and large groups.

Want a good powder for accuracy with 9mm at faster action pistol burn rates?  If you like Vihtavuori, N320 is a much better option for accuracy, and still a fast burner.  Bullseye is my go-to.  American Select is grossly under-rated.  Prima-V has been good.  HP-38/Win231 and Titegroup have been perfectly acceptable. If you're willing to go to slower burning powders, for pure accuracy, Power Pistol might be top dog.  Silhouette is excellent.  WSF is also very good, and a little more in the middle between fast and slow.  There are others.  

No one notices the recoil difference from one shot to the next with an extreme spread of 27 feet/sec, which is a PF swing of 4 with 147gr bullets, so don't tell yourself that a PF of 131 is providing you some recoil advantage over a PF of 135.   You'll never notice it.  

Want to make it extra easy?  Drop down to 124gr bullets and don't put too much value on low power factor.  Ladder up .1gr at a time, and somewhere between 131 and 138, you're almost guaranteed to find a gem.  

 

[9x45]

I wouldn't bother bumping just .1 grain at a time as all Dillons will throw +/- .1 grains from the hopper with sugar powders and up to +/- .3 grains with corn flake powders. Just load it to max OAL and bump .2 grains until it tightens. Then shorten your OAL by .020" until it opens up. Both my G17s have fitted barrels, by Irv Stone himself.

[Jetskidawg]

I had very good luck with MG 147's and N320 at 1.125 OAL.  Flat, soft, and accurate.  Same same with MG 124 JHP's and N320 at 1.125 OAL, just a little more snappy.  Factory barrel.

[rdinga]

Two 147 bullets that seem to work well in my Glocks:

 

Zero 147 JHP

Precision Delta-147FMJ-TC

Either bullet loaded ahead of 4.0 grains of WSF, COAL of 1.10, and CCI primers do well in everything from my 43 to my 17L.

[Red Ryder]

Unless you are using a ransom rest, it could just be you, those glock sights, and your loads. Probably a combination of all three.


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[Scootertheshooter]

You do NOT need an aftermarket barrel.  The stock Glock barrels will produce 2-inch groups at 25 yards all day.  What you NEED is to load for accuracy instead of recoil.  A Blue Bullets 147 loaded to a PF of 131 with N310 is pretty much a perfect recipe for soft recoil and large groups.

Want a good powder for accuracy with 9mm at faster action pistol burn rates?  If you like Vihtavuori, N320 is a much better option for accuracy, and still a fast burner.  Bullseye is my go-to.  American Select is grossly under-rated.  Prima-V has been good.  HP-38/Win231 and Titegroup have been perfectly acceptable. If you're willing to go to slower burning powders, for pure accuracy, Power Pistol might be top dog.  Silhouette is excellent.  WSF is also very good, and a little more in the middle between fast and slow.  There are others.  

No one notices the recoil difference from one shot to the next with an extreme spread of 27 feet/sec, which is a PF swing of 4 with 147gr bullets, so don't tell yourself that a PF of 131 is providing you some recoil advantage over a PF of 135.   You'll never notice it.  

Want to make it extra easy?  Drop down to 124gr bullets and don't put too much value on low power factor.  Ladder up .1gr at a time, and somewhere between 131 and 138, you're almost guaranteed to find a gem. [emoji6] 

 

124's and HP-38 all day long

[jcc7x7]

3.0grs, e3,wsp,147 Bayou,1. 135col

2.0"@25yds,134pf, glock34 mos.

Same load I shoot out of 2 1911's and Sig 226

[MikieM]

The Glock 34 I had was a real dog with the factory barrel.

I switched to a drop in Wilson Combat, and problem solved. Outstanding accuracy.

Loads affect accuracy, that's for sure, but they are something you fine tune after you have the correct set-up in your gun.

[9x45]

To be fair, a local LEO agency got some new G34's in and they won't go group for Shiite.  Glcok rep took them all  back.

[GrumpyOne]

12 minutes ago, 9x45 said:

To be fair, a local LEO agency got some new G34's in and they won't go group for Shiite.  Glcok rep took them all  back.

A problem with Glock accuracy? Say it ain't so!

[Scootertheshooter]

To be fair, a local LEO agency got some new G34's in and they won't go group for Shiite.  Glcok rep took them all  back.

To be fair to glock might be user error in this case[emoji38][emoji38][emoji38][emoji38]

[9x45]

Nope, the Dept Range Master is a Master Class L10 shooter, it wasn't just some new deputies. The West Coast glock rep agreed after watching out guy running 2'  groups at 25 yards with a duty issue G21s and G17s

[rustybayonet]

I'm with the 124 gang. I can make more accurate rounds with almost any 124 over a 147. 

[Darrell]

On 12/15/2016 at 0:29 PM, rustybayonet said:

I'm with the 124 gang. I can make more accurate rounds with almost any 124 over a 147. 

I agree with everyone else on 124 gr bullet. Much more accurate than 147's. I've done extensive testing and all my 9mm shoot 124's better. To get a 147 to be more accurate you will need a barrel with a 1in10 twist, not a 1 in 16 as if most 9mm. Some bullseye shooters run 1 in 32 twist with 115's for great 50 yds accuracy but they only have 1 or 2 guns built specifically for bullseye shooting, I have over 10 so the cost would be prohibitive. It was far easier to learn to adjust to the recoil impulse of 124s than to spend money on a custom 1:10 twist barrels. 

[Steve RA]

"

Nope, the Dept Range Master is a Master Class L10 shooter, it wasn't just some new deputies. The West Coast glock rep agreed after watching out guy running 2'  groups at 25 yards with a duty issue G21s and G17s"

 

Doesn't seem as though those would be terribly difficult to equal.

[rpm8300]

Thanks for all the input guys - lots of good points.  Long story short, 124 Precision Delta JHP will group 1.5" with pretty much any powder I use, Titegroup, VV310, Autocomp.

I'm still playing with loads but one 147 load that was very accurate is:

147 Plated Rocky Mountains

3.7 WAC

1.16 OAL (pass plunk no problem)

127PF

Fed SPP

This gives me 2" groups consistently and is a good feeling load.