Another use for PB checks?

[wallacem]

First thing you all are gonna say is "how stupid" but I wonder if it will work. I have these 110 gr jsp bullets made for the 30 carbine. They actually measure .307. I use them in several different 30 cal loads, and thought I would try them in the 7.62x39, which is .311 dia. I used a pb check on them, ran them thru my .311 Lee sizer and plan to shoot them in the 7.62x39. What do you think?

[racepres]

Being ignorant, I know Not what a PB check is...But I really appreciate the ingenuity shown here!!
Shoot em and see!!!!

[wallacem]

Sorry bout that. PB checks are gas checks made to go on a plain base cast bullet. They are stamped from aluminum coke cans or other thin material, formed like a cup and run thru a sizer on a plain base bullet to attach, to help prevent leading in the barrel. I am using them here to simply make these jacketed bullets larger. Wallace

[BK7saum]

While it will probably give a good seal against blow-by, i don't see how it would improve any accuarcy in a 7.62x39 barrel.

Give it a try and hopefully you'll have promising results.

[Grayone]

First thing you all are gonna say is "how stupid" but I wonder if it will work. I have these 110 gr jsp bullets made for the 30 carbine. They actually measure .307. I use them in several different 30 cal loads, and thought I would try them in the 7.62x39, which is .311 dia. I used a pb check on them, ran them thru my .311 Lee sizer and plan to shoot them in the 7.62x39. What do you think?

Try accuracy testing with and without and it will tell you quick if you are just wasting your time. Let us know what you find out.

[405grain]

The mechanics of it suggest that these shouldn't be very accurate. The nose of the bullet might tip in the bore relative to the bore axis. This tipping will probably be in random directions for each cartridge chambered. The accuracy might be poor but: stranger things have happened. You won't know if it'll work until you try it! I hope you get good results.

Also, a second thought: Powder coating can be used to bump up the diameter of bullets. There's no rule that says you can't powder coat jacketed bullets. Just another thing to try if the gas checks don't work out.

[wallacem]

I will load up some and report back.

[Dusty Bannister]

Before you get too far down the testing, try gently pressing a jacketed bullet through the barrel without a check. If it resists, then you know the body of the bullet will be supported on the lands, and the check will act as a base seal. Might work better than expected. If the bullet free falls through the bore, then post #6 is probably the answer.

[missionary5155]

Artillery rounds have a ring around the base for the gas seal. The body is a bore rider + but not groove size.
So "if" the bullet is a bore rider it should work better.

[truckjohn]

If you pull factory 7.62x39 ammo, you will find most of the bullets are 0.308 or so. They bump up to barrel size pretty fast.

I would be more concerned about the PB check being left in the barrel.

[Nueces]

fI would expect your gas ring bullets to work well, especially if breach seated. Seating in a case neck might cause a loose fit as the check is bigger than the shank.

[wallacem]

OK, report/ Went to range today. The group on left is 10 shots with the checks on the bottom of the bullet. The target on right is 10 shots without. The naked bullets grouped a little better, and the two shots in the black bull were two extra I had loaded with naked bullets. They would have been right in the middle of the naked group on the right. This is alll at 100 yds. This little gun will group under an inch all day with 125 or 150 gr bullets. I can;t really fault either of these groups even though they are not quite as god as heavier bullets do. Fact is, they will kill a deer all day long, and I have a box of about 1900 of them. They also shoot real good in my 30-30 Encore. Given these groups I think it is a waste to put the checks on. Wallacem
See target below.

[wallacem]

[Grayone]

Thank you for the feedback on testing. Looks like you have a pile of good plinckers and could sub for closer range varmint hunting.

[wallacem]

A roundnose 110 gr 30 cal bullet traveling at 2500 fps makes good deer medicine. Wallace

[nanuk]

a chronograph should be able to tell you if you have blowby/gas cutting

if you do, then the check is an advantage due to barrel life, even with reduced accuracy

but, you might play with your load to see if you can tighten it up a bit


I used to have a 500BPE, the bullets designed for that rifle were small bodied, just over bore diameter, with a ring around the base that was groove diameter. they worked fine. Woodleigh was the brand.

I would think it would act as a bore riding CB, allow a slight increase in velocity with lower pressures.
but the main concern for me is erosion due gas cutting