Help first time barrel slugger-puzzled

H&R Glock · Nov 30, 2020

You may have been following my persuit of a perfect load for my TTC Tokarev. I've decided to slug my barrel. The 7.62x25 is supposed to be about .311"
I did not have any soft lead balls of a similar caliber but I had Berry's plated lead 32 caliber 71 grain bullets. They are supposed to be plated soft lead. SO,,,,, In the muzzle it went and the results have me puzzled!
There are 4 neatly carved grooves in the bullet where the lands reside in the bore. There are no depressions in the bullet where the grooves are supposed to show up. That tells me the groove diameter is over .312" or possibly over .3125" which my micrometer tells me when I mike a new bullet.
Am I doing this right???? Is the bore actually as loose as .313"??????????? Is the bore "shot out"??? Was using a plated bullet an incorrect tool?

mdi · Nov 30, 2020

While I don't think I would ever use anything but lead for slugging, your slug seemed to work. If there are no marks or swaging down of the bullet between the rifling, the groove diameter is larger than the bullet diameter. Did you measure the large diameter of the slug? I'd suggest using an egg sinker and try 3 or 4 slugs (lube the slug, oil the barrel and carefully pound the slug through with a brass rod). For most of my slugging I like the slug to be about .010" larger than suspected groove diameter,

Another way to get good slugs for slugging a barrel is to pour some melted lead into a fired case. When cool, remove the slug with an inertia puller. Your slug will be tapered and the correct diameter.

fxvr5 · Nov 30, 2020

That's not unusual. My Tok barrel slugged at .3128.

Most bore's are oversized. For example, the 9mm has a SAAMI groove diameter of .355, but they will almost always be larger, .356-.358. That's still within spec because the SAAMI spec is .355 +.04, so even a .359" groove diameter is within spec.

You should always start with an oversize bullet, like way oversized. Try a .315 to .316 slug to make sure it is swaged down by the grooves.

PWC · Nov 30, 2020

mdi said:
Another way to get good slugs for slugging a barrel is to pour some melted lead into a fired case. When cool, remove the slug with an inertia puller. Your slug will be tapered and the correct diameter.

Met my quota of learning something new every day.....makes too much sense, especially the taper.

Thanks

kelbro · Nov 30, 2020

Squish the Berrys lengthwise with some pliers to make it 'fatter' and then try again.

H&R Glock · Nov 30, 2020

mdi said:
While I don't think I would ever use anything but lead for slugging, your slug seemed to work. If there are no marks or swaging down of the bullet between the rifling, the groove diameter is larger than the bullet diameter. Did you measure the large diameter of the slug? I'd suggest using an egg sinker and try 3 or 4 slugs (lube the slug, oil the barrel and carefully pound the slug through with a brass rod). For most of my slugging I like the slug to be about .010" larger than suspected groove diameter,

The new Berry's bullet (as shown in the picture) is .312" or .3125 depending on where my micrometer grabs it. MDI hit it on the head with "the grove diameter is larger than the bullet."
I'm gonna look for some slug sinkers that will work, but for now I think I will no longer put the 32acp bullets through the .309" sizing die for loading, but instead load them up "as is" for plinking ammo.
The whole idea was to determine if plated 32 acp bullets were safe to shoot in the Tokarev as is. I believe I proved that to be the case This will put me back in the CHEAP AMMO business.

DocRock · Nov 30, 2020

Berry’s isn’t very soft lead. For slugging, you really want BHN 6-8. Berry’s are BHN15 or more. What happened was the lands engraved but there was insufficient obturation to squeeze bullet into the grooves. So, use a softer lead or use Cerrosafe to make a cast.

Bfh_auto · Nov 30, 2020

There is one other issue when loading for a tokarev.
The barrel slugs it over size while the neck of the chamber can slug out undersize.
I ran into this. Anything over a .309 bullet caused feeding malfunctions from the neck being too large for the chamber.
I needed. 311 for the barrel.

FROGO207 · Nov 30, 2020

Well I never have tried to slug with a plated bullet. You could wack the point of the bullet with a hammer to see if you can expand the sides but a lead slug that is large enough diameter to show where the whole thing dragged as it went through the barrel is what you are looking for. That bullet might or might not bump up to seal. Were you having problems or just doing this to see what you have?

H&R Glock · Nov 30, 2020

I found a sinker.

What I'm trying to do is find the cheapest bullet I can use and get the best accuracy from it and also find out how wildly my rifling varies from .311"

It's .3135" The rifling is very shallow.
I fired one Berry's 32 acp full size with no pressure signs. Used 5.0 grains of Accurate #2. It was not hot enough to function the pistol.

Tomorrow I will fire several full size 32 acp bullets with 5.7 grains of powder. This charge consistently rendered perfect function of the gun when I was using bullets sized down to .3095" This load showed no high pressure signs. Don't worry I'll have my wife stick her fingers in my ears!

Stand by for report from my computer room or from the hospital.

FROGO207 · Dec 1, 2020

Did the lead one pound through easier? Cheaper would be Hi Tec coated lead 32 cal bullets. Think missouri bullet or RMR reloading.

Blue68f100 · Dec 1, 2020

H&R Glock said:
I found a sinker.
View attachment 959374
What I'm trying to do is find the cheapest bullet I can use and get the best accuracy from it and also find out how wildly my rifling varies from .311"

It's .3135" The rifling is very shallow.
I fired one Berry's 32 acp full size with no pressure signs. Used 5.0 grains of Accurate #2. It was not hot enough to function the pistol.

Tomorrow I will fire several full size 32 acp bullets with 5.7 grains of powder. This charge consistently rendered perfect function of the gun when I was using bullets sized down to .3095" This load showed no high pressure signs. Don't worry I'll have my wife stick her fingers in my ears! Stand by for report from my computer room or from the hospital.

That sinker has the color of Zinc. Was it hard to get through the barrel?

mdi · Dec 1, 2020

That looks like a good slug. I would make up a couple dummies and see if they chamber with a .314"-.315" bullet. Shallow rifling is typical of some European/surplus guns. Now you are learning more about your gun (not every gun is what it's "supposed" to be!). And that's a good thing...

H&R Glock · Dec 1, 2020

Test firing went beautifully. I still have about 700 Berry's bullets left on my bullet shelf. The bullets were used in the past to load for my two 32 acp pistols. When I need more the High Tech coated bullets will be my next experiment. Thanks Frog!
The lead sinker went right in the bore and the muzzle cut a perfect donut of lead off the sinker. I had to give it about 4 whacks with a steel punch until it got close to the muzzle then used a nylon rod to sink the lead through the bore.
Despite the snow on my deck I found all of my brass after the test firing. All brass looked normal. Later today I will chrono this new load and see if the velocity increases over the 1050ish FPS achieved with the .309" slugs.
Anyone else loading this round would be advised to use the absolute minimum belling of the case mouth. My loads have very strong neck tension despite the short neck of the design.

H&R Glock · Dec 7, 2020

Chrono'ed the last loading: 71 grain plated .312" Berry's bullet with 5.5 grain of Accurate #2, averaged 1370 fps.(no signs of over pressure)
Quite a gain over the 1050ish fps with .309" bullets.

Help first time barrel slugger-puzzled

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