I slugged my Glock barrel... What size/lube kit should I use?

[dfwbiofuels]

So I took the time to slug my barrel yesterday in my Glock 17.

Just a hair under .356.

At this time, I'm planning on using the stock barrel. So if I fit the boolits properly (here's my question) and lube well (LLA) then I should keep leading to a minimum.

These bullets and the ammo they will be used in are for plinking or competitive IDPA style shooting. So the velocity will be about 950fps for a moderately lighter recoil.

My alloy is from a mix of wheel weights and linotype so its very hard.

Is the "rule of thumb" to go .001 larger than the slugged diameter in the barrel if the barrel has radiused (polygonal) rifling?

I'm almost convinced that I should order the .357 Lee bullet sizing die but I'm afraid of bulging the cases from the larger bullet.

Has anybody here found a good solution for choosing the right sizing die?

[Shiloh]

I size my to .358 this for a LEE 125 gr. RN. That pistol, factory barrel.
It just touches the parting lines. Accuracy is enough better than .357 to make a difference.
9mm was the hardest caliber so far for me to get running accurately.

Shiloh

[dfwbiofuels]

Shiloh,

Thank you.

Would you mind sharing your load details? Powder, COL?

Are you using the Lee mould for 125gr 356 with the single lube groove?

[MtGun44]

Measuring this with a caliper is highly questionable. You need a micrometer, since the
error spec on calipers is +/- .001.

If it is actually .356, you should shoot .357 or .358 for best results in most 9mms.

Bill

[MaineJim]

If you use a pure lead slug you will find your bore closer to .355. By using a very hard boolit to slug the bore you get a certain amount of springback that skews the results.
My Glock 17 and 26 both slug at .355 and work flawllesly without a bit of lead left in the bore.
My boolit is the RCBS 124 CN,felix lubed,4.4 grains unique COL 1.080.
I tried them sized sized at .358 since they drop at .3585 and had two blown cases out of fifty fired.
Didnt even know it happened untill i picked the cases up,i guess not enough gas escaped down in the magazine area.
The boolits are not being pushed back in the case either,anyway i know a lot of people have great results with .358 diameter bullets but in my case its a no go.
I forgot to add that i size my boolits at .356 and that back in the late eighties i had a Glock 19 that shot very well with the same diameter boolit as well,course back then didnt yet know about slgging bores.
Try your boolits at .356 and if they dont work well then got up to .357,i would try .356 first.
Im sure you wil have that Glock shooting right,i find them less fussy in 9mm than other pistols and my model 30 .45acp shoots like a target pistol,minus the target
trigger but good work can be done with a Glock trigger with enough practice.

[evan price]

My Lee .357 sizer leaves my boolits about .3565 actually, which is darn near perfect for my 9mms.

[Shiloh]

Shiloh,

Thank you.

Would you mind sharing your load details? Powder, COL?

Are you using the Lee mould for 125gr 356 with the single lube groove?

Yes, that boolit. The only boolit so far that has a large enough diameter.

5.6 gr. AA#5 cycles fine. Max load is 6.2
My OAL is long. 1.25. No marks on ejected live rounds.
Crimp to just close the bell on the case mouth.

This is what I use. See what works best for you.

My next experiment is a slightly larger powder funnel/case expander. Maybe then I can use a smaller boolit.
So far though, I'll stick with what works till I have time.

SHiloh

[dfwbiofuels]

If you use a pure lead slug you will find your bore closer to .355. By using a very hard boolit to slug the bore you get a certain amount of springback that skews the results.
My Glock 17 and 26 both slug at .355 and work flawllesly without a bit of lead left in the bore.

Jim, thanks for sharing your experiences. I'll keep the springback effect in mind. If that's the case, then wouldn't it stand to reason that the bullets I size will also springback a bit?

My boolit is the RCBS 124 CN,felix lubed,4.4 grains unique COL 1.080.
I tried them sized sized at .358 since they drop at .3585 and had two blown cases out of fifty fired.
Didnt even know it happened untill i picked the cases up,i guess not enough gas escaped down in the magazine area.
The boolits are not being pushed back in the case either,anyway i know a lot of people have great results with .358 diameter bullets but in my case its a no go.

Good to know.

I forgot to add that i size my boolits at .356 and that back in the late eighties i had a Glock 19 that shot very well with the same diameter boolit as well,course back then didnt yet know about slgging bores.
Try your boolits at .356 and if they dont work well then got up to .357,i would try .356 first.
Im sure you wil have that Glock shooting right,i find them less fussy in 9mm than other pistols and my model 30 .45acp shoots like a target pistol,minus the target
trigger but good work can be done with a Glock trigger with enough practice.

I've got the lee sizer in .356 and based on your suggestion, I'm going to recheck the bullets for springback after running them through.

I'd like to get a 45ACP Glock 21 in Gen4 or the Gen3SF. But that's going to be after I make another large investment to upgrade from my Lee Loadmaster to a Dillon 650.

As far as triggers go, I'm experimenting with a lighter striker and safety spring with the OEM connector and all other parts original. Side by side, the takeup is better and the pull weight is reduced. Still not a 1911 but it never will be.

[dfwbiofuels]

My Lee .357 sizer leaves my boolits about .3565 actually, which is darn near perfect for my 9mms.

Do you know what the BHN is of your alloy and would you mind sharing which mould you are using to cast your 9mm boolits?

[dfwbiofuels]

Maybe I should mention that I'm using a Lee 6-cavity mould, 124gr RN TL. They are dropping out at .360 to .358 as I roll it in the caliper. So they are a bit out of round. I'm told that this is quite normal.

[dfwbiofuels]

I use RCBS 124 gr GC RN in both my glock 26 and glock 17. Sized at .357. No leading and great accuracy.

Thanks. Have you mic'ed your sized bullets to know exactly what the diameter is?

[TheSuperfan99]

I shoot cast through my glocks as well. I have a Lee Sizer die for the 9mm at .356. BHN is currently 16-18 (water quenched) and I employ Barry Darr's pan lube recipe. I use the same recipe in all of my glock barrels and it works great. I'm about 1000 rounds fired through the Glocks, the next sign of leading or gas cutting will be the first.