Sluging a Smith & Wesson 9mm Luger. Mod.5946

[bgokk]

1. Drove a lead egg sinker through the bbl. after giving the barrel a coat of oil.
2. Cut a strip of aluminum from an Aldi's diet cola can.
3. Using 2 different mics, a. is a Harbor Freight digital & b. an old worn Starrett, both checked for zero. I determined the thickness of the strip of aluminum to be .0038". The mics agreed.
4. I wrapped the strip around the slug and holding the ends tight around it with parallel pliers I took several measurements with both mics a. & b.
5. I totaled and averaged the measurements from each mic, a. = .35784" & b. = .35988 Do you see where this is going?
6.I subtracted twice the thickness (.0038"x 2 = .0076") of the aluminum strip from each of the above average diameters. The slug (groove diameter) from a. is .35024" and from b. is .35228"

Every time I read a thread about 9mm and leading I see recommendations for using .357" and even .359" boolits.

WHAT HAPPENED TO MY BARREL?? I must have gotten it wet and it shrank.

Something went wrong. I cannot believe my groove diameter is that small.

Brooks

[Piedmont]

Why don't you pound your egg sinker in from the chamber end and just start it into the barrel, then knock it back out to the rear. Measure it in front of the chamber before you get the groove marks and go with that. Less math, better results.

[bgokk]

Why don't you pound your egg sinker in from the chamber end and just start it into the barrel, then knock it back out to the rear. Measure it in front of the chamber before you get the groove marks and go with that. Less math, better results.

That would give me the chamber throat but would not give me the barrel diameter.
Brooks

[Piedmont]

Yupp.

[wingnut49b]

If you want the barrel measurement, I have just driven the slug through the whole way. Then measure it directly. I've not ever wrapped any aluminum around the slug to measure.

[383]

If you want the barrel measurement, I have just driven the slug through the whole way. Then measure it directly. I've not ever wrapped any aluminum around the slug to measure.

I have a S&W 3913 and 5906 and have been trying to measure after slugging my barrels, but due to the odd number of grooves, you can't do a direct measurement.

[williamwaco]

I suspect the slug was not completely filling the bore and is thus smaller than the bore.

When I slug the barrel of a 35 caliber handgun I start with a 35 caliber bullet cast of soft lead and carefully selected for a minimum diameter exceeding .360.

[bgokk]

I suspect the slug was not completely filling the bore and is thus smaller than the bore.

When I slug the barrel of a 35 caliber handgun I start with a 35 caliber bullet cast of soft lead and carefully selected for a minimum diameter exceeding .360.

Here is the lead that sheared off when I drove the sinker through the S&W barrel. What do you think? 9mm case for size.






Brooks

[292]

I've checked the 2 Smith 9mm barrels and they both ran small. I haven't got my notes in front of me but I think just under .355. I use a .356 Lee sizer with good results.

[williamwaco]

Here is the lead that sheared off when I drove the sinker through the S&W barrel. What do you think? 9mm case for size.






Brooks

I think my theory was not correct.

[Char-Gar]

Mucho work for no meaningful information. The groove diameter of your barrel is .354 - .355. Size your bullets .358 and worry no more. No sense making this stuff so complex when there is nothing to be gained by doing so.

[Jim..47]

Question: How are you able to make the slug a particular size, as mentioned above? Do you sand down the sizing die or what?

[bgokk]

Question: How are you able to make the slug a particular size, as mentioned above? Do you sand down the sizing die or what?

I am not sure what you are asking.
The slug is an over size piece of soft lead (larger in dia. than the groove dia. of the barrel being slugged) which is driven through the barrel.
Slugging is done to establish the groove dia. of your barrel to get the right size (dia.) boolit (+.001 or .002) to avoid gas cutting and leading.

Brooks

[40Super]

Jim , He poured lead in a 9mm case and cut the slug out. I took a block of steel and did several helical endmill bores to make slugs about .008" over my different calibers. The empty case method is a good one and easier to make.
I think the op may have gotten the slug tipped when it was shaving lead at the beginning. It probably made the od too small then. I've had that happen when using a hammer. I now use a press for a nice even ,steady pressure(+lots of grease),my slugs come out great. Try again, this time about 3/4" from the end try to "fatten" the slug back up by putting a brass/copper rod up into the other end to crush the slug a little, then resume pushing the rest of the way out.

[bgokk]

Mucho work for no meaningful information. The groove diameter of your barrel is .354 - .355. Size your bullets .358 and worry no more. No sense making this stuff so complex when there is nothing to be gained by doing so.

We gained interaction!
I am not yet loading boolits for the 9mm. I am just trying to get my ducks in a row so I may avoid some of the 9mm pitfalls.

I just could not understand how I got the very small groove dia. I actually slugged the barrel again using a ML round ball and came up with the same number.

I will, when I start loading for 9mm be using .358".

Brooks

[40Super]

The problem with just picking a number is that many barrels that are on the "small" size also won't chamber the oversize boolits. I have three barrels right now that won't chamber any lead slug that is bigger than J=word sizes. Then the other barrels will chamber .003" oversize. That's why I prefer to slug.

[Jim..47]

Thanks for the explaination 40 Super

[Cane_man]

why can't you just take a lead boolit, then tap it on the nose with a hammer? do it carefully and the boolit OD will expand 0.05 ~ 0.10 just right for a slug

[Char-Gar]

I have yet to encounter a 9mm firearm that won't chamber and fire a round with a .358 bullet. This includes a dozen or more us and euro handguns and a couple of sub-guns.

[40Super]

My XDm 9 and a Storm Lake NM 9mm conversion for my XDm40. Both slug at .3555 and a .357bullet barely fits. .358 will jam 70% of the time. It IS because they won't chamber a .358 bullet and not any other reason. My other barrel is a 45, that is tight also.