Does anybody know how the use of an overshot card affects pressure? I know they are good for holding in buffer, and they make it easy to get an even crimp, but what's it really doing?
I use the overshot card to flatten the crimp so I don't get leaks on my 12-gauge 5/8 oz loads. I doubt that it increases pressure enough to provoke concern as I'm already on the ragged edge of a non-cycling 1100 with these loads. BTW, I use 24-gauge cards because I happen to have a bunch on hand.
I doubt very much that an OS wad would make much of a difference in terms of breech pressure. In "the old days" we used OS wads in roll crimped hulls. There was some concern as to whether the wads harmed patterns. As a result many of us used 16 gauge OS wads in 12 gauge loads. I have no idea whether the practice did any good but I suspect it did no harm.
Exactly why I use an overshot card...to flatten out the crimp (esp. on those crappy Win. hulls). They seem to be useful with my 7/8 oz loads where I get a little more dishing than usual. So far I haven't noticed any different performance in pattern with or without.
There is a fellow who posts on here now and then that makes and sells them. He services the cowboy and black powder shooters market. I hope somebody with lively brain cells can come up with his moniker.
If you are talking about 12 ga loads and you will be using lots of OS wads you can make them yourself, cheaply and easily.
Go to McMasterCarr.com and buy a 9/16 hollow punch for about $10. Then go to Wally world or anyplace that sells plastic cutting boards and buy the cheapest one you can find. Get one that's about the size of a sheet of paper. Don't use wood or any other material because it will dull your punch pretty quickly. Next, using cereal boxes, cracker boxes or any similar paper material start cutting your own wads.
Total price is about $15-$18 and the punch and board will last longer than you will.
If you are talking about 12 ga loads and you will be using lots of OS wads you can make them yourself, cheaply and easily.
Go to McMasterCarr.com and buy a 9/16 hollow punch for about $10. Then go to Wally world or anyplace that sells plastic cutting boards and buy the cheapest one you can find. Get one that's about the size of a sheet of paper. Don't use wood or any other material because it will dull your punch pretty quickly. Next, using cereal boxes, cracker boxes or any similar paper material start cutting your own wads.
Total price is about $15-$18 and the punch and board will last longer than you will.
Art,
GMTA! (great minds think alike). All of the above except I found a cheapo set of punches that cover from 1/4" - 1" by 16ths". Gives a variety of possibilities for under and over cards for all the gauges.
Cheers,
R*2
I will be using them under lee key drive slugs. its said that a .125 20 gauge card is need to help with wad deteriation.so I`m thinking something harder than just cardboard is needed. the slugs I have shot without a card embed themselves almost a 1/4 of an inch into the wad..
sorry about taking over this thread I will start a nother if needed.
skid,
With a range of household materials from eggshell carton foam to corr. cardboard to solid, eg. cereal box cardboard, I'd be taking some of the compressed paper and simply trying multiple layers. Other plastics? Dunno', once you've got a punch or punches you can experiment to your heart's content.
Cheers,
R*2
I too punch my own overshot cards mostly from cardboard milk containers. I have also used plastic milk jugs.
I have also used sheet Tyvek from a local home improvement store.
Once you get a nice set of punches you can punch a lot of overshot cards. I usually do mine sitting on the floor while watching TV.
If you load high volume this will save you some serious coin. Also much easier to ship to Canada, eh? Although I doubt the Mounties care about little cardboard discs.
Since I roll crimp all my shells - I have to use overshot cards on all my shells. I really like the clear overshot cards that BPI sells but they get a little expensive in large lots. Do not know if anyone else offers a similar clear plastic overshot card.
I found about all the boxes that have a slick finish on one side from paint or print are about .020 thick. You can stack as many as you need to get your crimp right or to reinforce your wad from collapse when you shoot buckshot. With the petals cut off the wad, I cut my os wads to .7 inch diameter
The factories found out LONG AGO that you need a VERY HARD basewad for slugs!
What happens is that on firing, the softer basewads are driven partially into the hollow base on SOME, but not all of the slugs. This totally destroys accuracy - one will be on target, while the next will be WAY off!
The factories use hard plastic discs of bore dimension above the overpowder wads, and place them under the slug!
skidd041, what recipe are you using that calls for a .125 20ga nitro card under the slug?
I have the loading data from Lee, and see no such thing.
Perhaps you are using the wrong wad/hull combination.
If you need a copy of the data, pm me with your email, and I will send you a copy.
I`m using the winn AA hulls , win 209 and waa12 wad. It was on one of the slug forums I read that the 20 g nitro card would help wad deformation and be more accurate.I might try one of the loads that use the fed wad to see how that works.
Yes, the Federal wads work well. Just be sure you use a straight wall hull such as the Federal, Fiocchi, Cheddite.
You can use the data for Federal hulls for any of them.
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