Question RE COAL/Bullet touching lands.....

Mikej · May 8, 2014

What do you think about having 9mm bullets touching the riflings/lands of the barrel? I'd seen/read somewhere that this is desirable, to a point, in reloading for rifles. This is the issue with my new Tanfoglio race gun with a polygonal barrel.....It seems that my already shortened OALs for the Wifey's Kimber 9mm are going firmly into the lands of the new gun, by close to .020. The loads I'd been making for her gun need to be no more than 1.085, and it seems I'm going to need to reduce OAL even more for the new gun?

I was blown away at how accurate this gun is. Once I got the sights adjusted I was able to get barely under a 2" group from rest at 50'. I don't wear my prescription glasses to shoot, I can see the sights but the target is blurry.

I keep close tabs on spent brass at this point still, looking for pressure signs, chamber blow-by, damage of any kind. I've had none. Recoil seems normal as does ejection. The gun has not had a single hick-up through 100 PMC 115gr ball, and 100 of my hand loads of 115gr Montana Gold JHPs pushed with 6.6gr of HS-6. So it seems the bullet isn't hitting the lands enough to stop the gun from going into battery, as happened with Wifey's gun. So I'm not sure what to do at this point.

Thanks

Mike

Certaindeaf · May 9, 2014

That's a very good question and what a fine pistol.
Personally, I'd load them such that they would be viable in all pistols.
If you're going to get funky whatsoever, especially in 9mm Luger, you'll find that you need to throat the chamber.

Mikej · May 10, 2014

Yes I would like to load the same for all our 9mm pistols, the issue comes in when the LC9 and SR-9c don't care, I can load the OAL as the book lists. I originally had to shorten the cartridge for the Kimber 9, and now it looks like I have to shorten it more for the Witness. I'm concerned of pressure spikes, though I am using the slower HS-6 which is slower burning than other common 9mm powders like Titegroup, Bullseye, 231.

I think its these Montana Gold bullets, the bearing surface is taller than other bullets in 9mm, 115gr and 124gr. They look somewhat odd loaded too, whereas the MG .357 bullets look normal.

I'm not sure what "Throat the chamber" means? And I feel I'm already getting funky with 9mm as I'm loading it pretty short. I am loading on the lower end of specs though.

Mike

Certaindeaf · May 10, 2014

Essentially the rifling starts too soon and or the conical (the most common) throat or leade needs to be relieved/cut at an angle to allow seating of semi wadcutters etc.
I'd really like to have a couple of mine done so I could chamber long seated semi wadcutters especially.