Cork GC ???

[iwottopq]

Hello dear friend.
My good friend Simone (aka Remington308) suggested me to use some wads under my cast bullets. These wads are used in Italian 8 m/m hunting cartridge called “Ottonella”, a kind of 8 Flobert but centerfire. This because I have finished my copper GC. These wads are made as a disk of cork with a paper disk above and another under. I loaded 25 cartridge with 163 grs cast bullets with the wads glued at the base, 6,0 grs of ww450 powder, fiocchi LR primers and military surplus brass. Other 25 cartridges the same but with 6,5 grs of WW450.
At the range (55 yards) the 5 shoots groups (of both loads) was about 10 cm (metallic sight and hand off, no rest), the recoil very low and the recovered bullets was without cork GC. After each shoot I inspected the barrel to view if the was any rest of the wads.
At the end…this is for me a interesting experience with a strange material…
Have you some similar experiences?
Ciao
Nino

[earplug]

About thirty years ago a shooting magazine article was published about using styrofoam cup material as a ablative for hot lead pistol rounds.
Basically a heat shield between the powder and the base of the bullet. I would think the cork would do the same thing.

[iwottopq]

Sorry, I forgot to specify that the gun was a Baikal single shot in .308 caliber and the average velocity of the 6,0 grs load was about 300 m/s and for the 6,5 grs was about 340 m/s.
Can I use this system to try shoots over the sound velocity without leading???
Thanks.
Nino

[Maven]

Nino, You can probably approach 500m/s with those cork seals, but that assumes a perfect cast bullet fit in your rifle's barrel and an excellent bullet lube. You'll know very quickly if it doesn't work as accuracy will be poor and bore leading quite evident. If that happens, remove the leading in the bore, reduce the powder charge by 1 or 2 grains (sorry, but I can't easily convert grains to grams or gram fractions), and try again.

[geargnasher]

I've used cork gasket material for lots of things, black powder and smokeless both. For smokeless, I had better results putting a tough card disc under the cork. Any sort of fiber cushion under a plain-based boolit helps seal the gases and protect the base. In my Savage .30-30 with 115-grain booltis there was enough room in the neck to put two 1/8" thicknesses of cork gasket material, this improved accuracy as well as bore condition up to about 550 MPS with no gas checks. Beyond that velocity accuracy suffered.

Gear

[iwottopq]

Hello to all.
Thanks for the replies.
For Maven: I use a alloy made with 70% of clip on WW and 30% of monotype alloy. The grease is home made with 40% of candle wax, 40% of beewax and 20% of vaseline. It, in pistol and.223, woks well, without signs of leading.
For geargnasher: Prior to use the cork disks I have used a flock of cotton over the powder but the accuracy was more poor than using the same components less flock.
Thanks again
Ciao
Nino

[303Guy]

... but the accuracy was more poor than using the same components less flock.That's an interesting side note! In that instance, were the boolit bases seated deaper than the shoulder?

[iwottopq]

That's an interesting side note! In that instance, were the boolit bases seated deaper than the shoulder?

Hello 303Guy.
I have tried seating the bases of the boollits above and under the shoulder but the result was the same, fewer accuracy than without the flock of cotton. I noted this result also when I shooted with reduced loads in my Remington 700 in .223 caliber and 58 grs boolits with hunting powder.
I have read in many books (all fron USA) that it is a good thing the cotton or dacron flock above the reduced charge...but with me it is not working!!!
Ciao
Nino

[geargnasher]

Nino, many of us here use Dacron with very good success, usually improving ignition consistency of certain powders, especially with reduced loads. How much are you using?

Gear

[Smoke-um if you got-um]

Nino,
More Dacron than needed can cause a loss of accuracy. Try reducing the amount you are using by about 30% and try 3 shots. If that does not work try 50% of what you are using now. Somewhere in there you will find the proper amount that will work for your particular cartridge. Another problem you might be having is that some powders do not like a filler and will not shoot accurately with it in place. Good Luck.

Mike

[iwottopq]

Hello to all.
For Geargnasher: I use about 1 or 1 1/2 grains of cotton becouse the dacron is hard to find in my city and seat it with a bit of pressure on the powder so it press the powder against the flash hole.

For Smoke-um if you got-um: I used S4 powder, an italian hunting powder made by SNIA and now, after I finished the S4, use the winchester WW450. With this I am exsperiencing quantity of powder starting from 6.0 grains. Now I am at 6.8 and I will try this tomorrow at the range.

For all: I have read on a book that I dont remember that is necessary to fill in a amount of dacron or cotton until the shoulder of the brass but I am very dubious on this theory. Have you any experience or news???

If it is important...I use a Lee factory crimp die at the end of the loading.

Thanks for your help.
Ciao
Nino