Gas check blues

[lastborn]

I have two 45/70 molds. One is 460425 FNGC and the other is a 460350 FNGC. Boolits drop .460 from both molds using 97pb-2sb-1sn alloy.I have a Lee .460 push through sizer as well as a Lee .4585 push through sizer.Using Hornady 7140 gas checks. Here is my problem / question: after running through either sizer I can pop the check right off with my thumbnail. I would think they would grip much better than that? Are they supposed to? If they don't stay on all the way to the target won't they be less accurate?
Please help! I want to load some rounds to get the gun sighted in, but don't want to waste primers,powder and lead in the process.
thanks

[onondaga]

Try the Lee .457 push through sizer, the GCs will be tighter. Your alloy is soft enough to obturate from that size unless you are shooting such really low pressure loads that a non gas check bullet mould would be more appropriate. If your gas checks come off as easy as you say, the brass crimp will pull them off also. I can attest to this by the dents they leave in my chronograph.

[frank505]

measure the unsized outside diameter of the gas check. That will answer your questions. Gator 458 checks are .470+ unsized and do not come off.

[UNIQUEDOT]

The only way they will be less accurate is if some stay on the bullets while others come off. With straight walled cases many people actually prefer slip on checks.

[Sagebrush7]

I"ve been told the Lyman Co. has always believed in slip on gas checks. According to the oldtimers if the check comes off in flight it has done its job. I still like to crimp them on tight.

[dicko]

It has been apparent that good fit of gas checks is a hit and miss affair. That's because of tolerances in moulds, and is to be expected. I have not had that problem myself, but I have noticed some variance of fit, jusy not enough, in my case, to be a problem.

When the problem is a consistent loose fit, the solution is easy, bore out the heel to a proper fit. Ideally, it should be a "snap" or tightish push fit. Then, to seat squarely, a seater should be employed to seat firmly and squarely before crimping while lubing. I use seaters I make on my lathe. They sit on top of the dies in my RCBS and Lyman lubers.

[legi0n]

Some gas-checks will come off no matter how well crimped they seem to be.
Here's how I know:
http://members.shaw.ca/le_r0umain/ChronyGC.jpg

[onondaga]

I finally made a file for printing new labels for my chrono for the same reason. I fill the dents with Bondo then put on a new label.

[tommygirlMT]

Super Glue --- or better yet the larger size bottles of the same stuff but better quality and better price that they sell at the hobby shops for the guys who do the flying RC airplane thing

Don't laugh --- it works so long as you super glue them on to the base of the boolit before lube ever touches the boolit --- you can even do it with pan lubed shot as cast boolits where the check never gets crimped and the check will still stay on all the way into the backstop and will still be stuck to the boolit when you mine the lead to remelt

[swheeler]

lastborn; anneal those gas checks and they may fit just right, lot of spring back in that big 45 cal check