need idea on how to make crimp on checks

[edsmith]

I have been thinking about how to make crimp on gas checks out of alu. so far brain freeze, can use some ideas on how to go about it. any one know how horndey makes theirs? thanks guys. may have to do it in two stages

[blaser.306]

I think that if you short stroked the cupping step it would leave a slight "flare to the mouth of the check . So when they are installed the final sizing would take place in your H+I die or whatever brand/color you favor ! just my oppinion YMMV.

[30CAL-TEXAN]

I'm not sure exactly what you are after but the aluminum gas checks I make "crimp on" just fine. I cannot pull them off by hand, I have to use a pair of pliers just like with the Hornady ones.

I think it has more to do with fit and thickness of material (at least for my purposes) as I have experimented with thinner materials and they did not crimp on.

I would guess that the little flare that is advertised on the Hornady checks is produced by stamping the disk (thinninng the center part) just before forming it into the cup. Not sure though, just my guess.

[Xcaliber]

30CAL -TEXAN ,I agree with you on that also. It has to do with the thickness you plan to use. I have also experimented with the thin material. The thinner the material, the worse it got as far as it staying on to my likes. I didn't want to double it . I would rather the material be of single
use for my die. The material I have now is .011 to .012 and works for me till I get to try some
.014 which is next in line once I get it.

[RU shooter]

What about a bit more clearance on the die when it cuts the blank it would leave a small burr on the edge,And during forming find a way so the burred top edge is a hair more open than the bottom so it would not iron it out. During seating sizing that burr would dig into the shank. And as others have said proper material thickness help alot.

[Swede44mag]

I have a problem with the Hornady checks on my 45-70 RCBS 300RNFP the boolits are to large to let the checks crimp on properly. I have tried thicker aluminum with my freecheck III maker it helps some. The problem is not with the crimp edge holding but the thickness of the material they are made out of. I still plan on getting one of Pat's check makers when he has them in stock.

[Swede44mag]

I have been thinking about how to make crimp on gas checks out of alu. so far brain freeze, can use some ideas on how to go about it. any one know how horndey makes theirs? thanks guys. may have to do it in two stages

You would have to roll the edge slightly while keeping it large enough to slip onto the base without shaving the lead.

So flair the cup then roll the edge in maybe?
I don't see doing it all in one operation.

[JeffinNZ]

I am interested to know why you want to. I find lots of my homemade gas checks in the rubber back stop at 100m. They don't come off.

[longbow]

I have thought the same about making crimp on checks which have a slightly thicker lip than sides.

I think they would have to be formed in a slightly tapered die where the die and forming punch swaged the sidewalls thinner at the bottom and thicker at the top. To do that would require ejection back up from the bottom rather than push through though. It might also require a little more oomph to form them.

I find that my 0.019" aluminum gutter checks extrude a little longer than typical checks and hang on real well anyway so I haven't bothered fixing what isn't broken.

Longbow

[edsmith]

the reason I want to do it, is because I can, mabey I don't have any problem with my checks staying on, I make my check makers to fit my boolit.

[Von Gruff]

I have concentrated more on getting a square edged base. Of course I have adapted and lapped my maker to allow the use of the various thickneses of litho and copper that gives the best results at different velocities from the different burning rate powders, and they hold on just fine. I did take some of the radius from the nose of the forming stem so that when driving the disc through the die and grounding on the hard base I do my forming on I get a flatter bottom without the pronounced radius to the sides of the GC. I tried to emulate the base of the Flat Base jacketed bullets so that there is a best (flat and square) probable face exposed to the final pressure push as the GC boolit leaves the barrel.

I think this has more effect than a thicker top edge to the GC, but that is just my opinion and YMMV.

Von Gruff.

[caseyboy]

Checks from my boolits that I find lying in front of the metal gong (200 meters away) are flattened out into a round disc. This tells me they are hanging on and flattening out on the gong. I use a Pat Martin check maker 30cal. I only press them on and run thru a Lee push thre sizer.