Proper Way? : Installing Gas Checks

[JWFilips]

Well It has been something I have been doing for years and I never gave it much thought. Never really read any "how to's" on it but there has to be some definitive method I would think.

Sometimes I fight with the buggers fitting them to the base. Pushing on them against the edge of my loading bench until my fingers are sore….before running them through the sizer. Sometimes using an expanding tool only to find that they are so loose I have to balance the bullet in the gas check on the ram of the sizer before running it home. (I use Lee pass through dies) Then should I run them nose first or base first?
Anneal or not to anneal? Seems every bullet mould I have needs a different method for installation!
Then are the truly on square to the base ??? I'm not sure
Some bullets it's easy and a pleasure; others are excess labor and pain!

I have even used a a cobblers hammer at times to form them flat on the base before sizing
I have done all of this ( & probably more)

Is there a "Proper" way?

 

[Brad]

Try adjusting the expanding tool a bit so it doesn't flare the check so much.
I like the Star for this as the bullet is nose down so the check sits easily on the base.

In the end it doesn't matter as much how the check is seated as long as it is nice and square on the bullet base and there isn't lead shaved.

 

[JWFilips]

Brad,
How can you be sure it is truly square?
Jim

 

[Brad]

If the base of the bullet is flat and the check doesn't shave lead it should be square. I also like a ram with a center cup or hole. By focusing the forces on the edges of the check it eliminates potential issues from a small sprue bump.

I have a feeling that if checks aren't square the target will let you know. I also have a feeling that small imperfections are ironed out on firing. At 20 K psi and up the check is going to end up firmly on the bullet when it leaves the bore even if it wasn't when it started.

 

[JWFilips]

At 20 K psi and up the check is going to end up firmly on the bullet when it leaves the bore even if it wasn't when it started.

Ok This makes sense to me!

 

[Ian]

I have a simple rule: If the check doesn't snap on with finger pressure, the mould gets sold down the river.

Hornady crimp-on checks are designed to work in a base-first sizer, and may or may not work in a push-through very well. The concave bottom and internal lip on the check work together to fold the apron of the check in and bite the shank. When the bullet is pressed against the seating stop of a lube-sizer machine it further squares the base and the pressure on the outside edge of the check give a final "bump" to the check metal to curl the cup closed and reduce its tendency to spring open again.

In a push-through sizer, going nose first, often the check will close up independently of the bullet being sized. Logic would dictate that the ram force pushing on the gas check would ensure it remains firmly against the bullet base, but this really isn't so. Once the bullet is in the sizer, it offers little resistance for the ram to push against, so really it's just pushing the check through. Base-first sizing in a Lee sort of has the same effect, once the check is sized it doesn't offer enough resistance to keep the bullet base pressed fully inside the check. The usual result is a gap between bullet base and gas check after sizing, even if the check was fully seated before sizing. When fired, this gap goes away, but the check pushes up a big ring of bullet metal in the process of seating in place and this may come loose and smear on the bore. Also, the check may fall off in flight because it doesn't have a good bite on the bullet anymore. Because of all this, I don't try to put checks on in a push-through sizer anymore, it just causes too many problems for me.

I have a solution to your problem, I think. Working on a drawing for a little doo-dad right now.

 

[fiver]

I have had issues with some checks from time to time.
they seem to either not press on to the base, or if I flip them over base first I get a domed base, but get the sides of the check pushed on fully.
most of the time I just press the checks into place by using the stars ram and a flat spark plug gapper tool.
then run them through the sizer.
if the bullet has about .001 to be sized in the die they go on straight.
depending on the check material I can quite often see the sprue nub right through it.

 

[KHornet]

This is something I never have paid a lot of attention to, as long as I get the
check on the base of the bullet. Snap on is preferred, but if I have to push it
on by using the base against the bench so be it. Agree that it will be flat on
the base via pressure as it is going down the tube.

Paul

 

[RicinYakima]

Also remember that Lyman bullets for many years, pre-1990, had tapered gas check shanks for their slip fit gas checks. Hornady's will usually work, but Gator checks will fall off.

 

[Intheshop]

Didn't catch if these were commercial or home spun checks.

Here,there's a cpl rigs that use "special" sizing dies which really,aren't.Instead,just fancy GC seaters.Meaning,the bullet is only pressed in far enough to seat/size the GC.

These are then "lubed" by hand with a small pen knife that has lived on my reloading bench for 30+ years.....giving a swipe of lube only to the space above check.Extremely accurate attention is given to the top punches.....to include custom D reamers that sort of,hybrid like size/shape these bore riders' noses.These top punches reach down to the first driving band.As such,because the top punch fits the nose so closely the checks sort of,don't have a lot of options?They are placed in the top of H die,bullet carefully centered then ram it,haha.Actually like a trigger,it's sqeeeeezed on.You feel the check slide,squeeze,crimp in a noticeable and repeatable fashion.Then through linkage flex on a stock 450,you feel the nose reshape.

There's two specific rigs that this management of seating works it's magic,both of which shoot bragging groups on a day to day basis.So accurate that it's humbling because,if a shot gets pulled.....uhh,it's the driver,NOT the rig.

Some rigs/cals get the Rodney Dangerfield approach.That is,throw'm in there with a flat top punch,hit the lube wrench and...forgetaboutit.

 

[Brad]

Reading the comments it seems we have a few separate issues.
Checks GOING on square.
Checks SIZING on square.
Checks STAYING on square.

Each requires a little different approach. Identify the specific problem and formulate a specific response.

 

[358156 hp]

I am in the minority of those who anneal their gas checks. It takes any "springback" out of them, and if I do my part the checks almost appear to have been cast into place, you can even see a shadow of the sprue cut. I use oversized base punches with my Star to help get the bases as flat as possible. The only issue with this is that most Star sizers don't have the punch perfectly centered with the sizing die. Therefore I can't have a super close match between the punch & the sizing die alignment.

I suppose we could give the Stars the "Perfesser" treatment. I still remember Keiths full-blown refit of a Lyman 450. That article doesn't seem to be online anymore, but Keith definitely showed the Lyman who the boss really is.

 

[Chris]

I don't always anneal, but when I do I think it does a better job. Also I use the gas check seater that Lyman provides with their lubrisizer.

 

[Ian]

I missed that article, sounds interesting! My 450 is in a box somewhere, it was a pile when brand new. The ram wobbles so badly in the bore that it would never start a bullet straight. The linkage pulls the ram first one direction, then the other, bending the bullet off center each way through the stroke.

 

[Rick]

I use oversized base punches with my Star to help get the bases as flat as possible. The only issue with this is that most Star sizers don't have the punch perfectly centered with the sizing die. Therefore I can't have a super close match between the punch & the sizing die alignment.

Are you using the punch lock nut? Try leaving it off allowing the punch to free float and self align.
.

 

[Intheshop]

358,seems like every onceinawhile when nothing else is stirring my grey matter,the thought of building a lube sizer is entertained.....Then,something more urgent comes along which puts the idea back to bed.

Looking at lube sizer manufacturing(Lyman,Lee,Star,etc) see's,at least in my pea brain an "attempt" to get it right.But,since folks accept their product,money and bean counters get the final word?Cast products have issues that tend to steer the engineering in ways that "may" not be to the best interests towards a more accurate product(talking machines here).Deep subject on different manufacturing concepts and approaches.

If we start with a clean slate design wise there is probably a better mousetrap....lube sizerly speaking.Take the cast,must make 10K units out of the process.Cast works great in compression but lacks strength in tension.The lube reservoir needs to be a separate,formula 1 fast,quick change part.Get that from the get go.Makes lube changes a snap.Make it steel so we can throw it on some heat to evac old lube.Make it as simple as running down to a plumbing supply and snagging a threaded 3/4 or 1" or whatever size,nipple.Done.

The alignment of top punches needs to be adj.The sizing die needs to be off the shelf....pick a brand.I'd also want adjustment in the articulation of the linkage ratio.....which is pretty easy really.We do it on certain machining fixtures now.

I can go on....just sayin,it isn't that big of deal.

 

[Intheshop]

I'll take the junker 450 Ian.....as a goodwill gesture.How about a trade or sumthin?

 

[KeithB]

For what its worth: I found the file(s) for my Lyman 450 rebuild on my backup drive. It's not a single Word file, it's a webpage with a lot of picture files that have to be in the same folder. I don't have time to turn it into a single Word file right now. When I get up my website in a few weeks I will put it up there and post a link to it on this site. Also have numerous other articles on machining and reloading equipment related topics I've written over the years that I plan to put up on my site for business purposes as examples of machine work.

 

[Brad]

Keith, please post the files of your bullet mould when you get your site up. That was some interesting work to follow.

 

[KeithB]

Will do.