Gas checks causing fliers

[toallmy]

I am hoping I have found the culprit that throws a occasional flier . Yesterday evening I finished installing gas check on a few cast boolits before running them through a push through sizer . When I noticed a few seamed to have a little more space just above the gas checks . My vision is shady at best but with my prescription reading glasses + my trusty magnifying glass I thought I had got the gas checks on fully . With thumb pressure alone , but after checking 40-50 my little digital caliper showed I have been WRONG .
In a pm with Larry a wile back , he mentioned to make sure you are seating your gas check good if using a push through sizer , I thought I was but I found a dozen or so out of around a hundred that were seated flat but not pressed all the way on the base .
Thanks Larry G .

[R. Dupraz]

That's why I don't use a push through sizers to seat GC's

[Dan Cash]

I bet you that when the propellant lights, that gas check gets solid against the bullet base. I would think poorly made gas checks with uneven skirts would be more likely to cause your fliers. How bad are your outlying bullet strikes?

[toallmy]

I bet you that when the propellant lights, that gas check gets solid against the bullet base. I would think poorly made gas checks with uneven skirts would be more likely to cause your fliers. How bad are your outlying bullet strikes?

I loaded the 12 that seamed the worst up to compare to 12 that had a well seated gas check to try on paper . But the temperature and wind made me put off my back yard testing . Just hearing the wind howling has kept me in the house today .

[rockrat]

I also had a flyer issue ruining a good group. Didn't think about the gas check coming off until one went thru my crony display and stayed in the mangled remains.

[Tripplebeards]

Im pretty sure I’m having the same problem with some lee 300 gr fn boolits I made 2 years ago. I forced them on with the lee sizer. I casted up a fresh batch yesterday, pc’d them with a thinner coat, and ALL the GCs snapped in place easily with my fingers. My fliers chrony about a 100 FPS slower as well so there might be something else going on.

Now as for my devastors the base must be wider because no matter what I do...even if I heat up the GCs I still have to individually tap them...or try to tap them flat lightly holding them in one hand and lightly tapping with a ball pine hammer to get them to somewhat seat before running them through my lee sizer. I get sub MOA groups with them though even after the the GC fitting drama.

[Dan Cash]

I loaded the 12 that seamed the worst up to compare to 12 that had a well seated gas check to try on paper . But the temperature and wind made me put off my back yard testing . Just hearing the wind howling has kept me in the house today .

Living in North Dakota, high winds and lo temps are not unheard of. We try to stay inside too.

[Dragonheart]

Since I powder coat my checks are bonded in place.

[toallmy]

I tried the dozen with gas checks seated poorly compared to a dozen rounds with flush seated gas checks . Although the 4 groups of 6 shots did not show me a lot of difference on target , I will be taking more time seating gas checks flush on the base of the boollits for now on .

[bmortell]

one of my lee molds don't like taking gas checks, shank is too big. I ended up putting the "pusher"? from the push through sizer on my turret press then rotate the turret half way between holes so its a flat to flat press. could probably recreate that on a single stage depending on what stuff you have. I hold the flat point on the "shell holder pusher" and press the check on squarely like that. guess that don't help if you have round nose. I would also assume they get fully seated by the gunpowder if not already but I cant imagine that helps accuracy when that's the case.


if that's not it maybe they're not sorted for defects well enough, or they need individually weighed.

[toallmy]

I have sorta started doing something similar with this particular mold and gas checks . With a bolt screwed in a press I first seat the gas check before running them through the lube sizer. I can feel the checks going on a little more on quite a few of them .
With my limited sample I couldn't say it really helped , but it definitely won't hurt to take a few more minutes seating the little devils .
I have several issues I'm trying to work through with this particular rifle + cast boolits combination , but that is the fun part .

[cwlongshot]

First ever LEE push thru sizer use for me was last summer. They are fast and efficient for sizing my PC bullets. Reading theu the directions I saw that you could seat GC WITH the push theu... I seated some 300g 454 bullets and when checking them saw uneven and incomplete seating. As there is no way to increase pressure, My first attempt with one was my last. Likly the added thickness of the PC made this apparent quicker.

Push thrus are great if you get right size... FOR SIZING.

I use my Lyman 450 for seating my gas checks.

CW

[Walks]

I seat my gas checks with the gas check seating accessory on my Lyman Lube-Sizer.

Puts them on Straight.

Don't trust the Lee push thru sizer since I started Powder Coating. Cheap **** dies are so rough on the inside they scrap off the PC.

[toallmy]

For clarification I'm using a magma push through lube sizer .
I have been sizing at .289 for a military surplus but due to me just barely sizing my cast boolits I have a problem with the lube actually pushing the gas check completely off at times if much pressure is used .
I have recently picked up 2 more sizing dies to play with different sizes one is a . 285 star dies that I plan to open up a little when I actually figure out the size that works better for my new project .
The other sizing die is a lee push through that started it's life at .285 . I am slowly opening it up a little at a time to test different sizes before deciding on how much to open up the .285 star die .
I recently put a new barrel on the rifle , and was a bit surprised to see the cast boolits sized at .289 do better than .285 so I decided I will try sizing at .285-.286-.287-.288-.289 before making up my mind on a final size .
In the end it may not make much difference on target but I enjoy shooting anyway + if I find that at .287 or .288 helps squeeze the gas check on a little tighter to keep them on when lube sizing its a good thing .

[JBinMN]

Maybe try putting a seating die that fits the profile of the nose of the boolit in a single stage press, & then using one of the "pushers" from a Lee die set in the shellholder, bring the gas check+ boolit up into the sizing die & I would think that with minor compression that the GC would be on the boolit flat & all the way.
Of course, some testing to find the right amount of pressure to make sure the GC is on all the way & flat would be in order.
Making sure the "pusher" is not too large for the particular seating die is something else to try, for example...
Maybe have to use a 45ACP seating die to do a .30 cal boolit/GC, or something like that. Experimenting would find a good mate to do this...

I think that is how I would try it if I did not have the crew here at CB.GL forum to give me tips,
& since I can't afford a lube sizer of any kind right now, I have to come up with other methods to get things done some times.

I have some .30 cal boolits to add some GCs to & that method above is how I will try to make sure that they are seated, if I find issues using the Lee sizer to install them. Have not run into the issue yet...

G'Luck! in solving your "flyer" issue(s) & fully seating your GCs!

[popper]

I bought some home-made GC, tap them on with hammer but still get occasional fliers. Hornadys don't have that problem. Still hard to seat them using the press and the screw-in NOE check expander plug.

[Bazoo]

I give gc'd bullets a little rap on the bench to seat them. Think I'll measure some next time.

[Stephen Cohen]

I bet you that when the propellant lights, that gas check gets solid against the bullet base. I would think poorly made gas checks with uneven skirts would be more likely to cause your fliers. How bad are your outlying bullet strikes?

I tested this theory last year and I agree with you, I found no change in accuracy as long as check stayed on, I don't powder coat but know some who do and as long as they keep the bases clean all is good. I guess the best idea is fit checks before coating. Regards Stephen

[Dragonheart]

One of the old physics demonstrations was to take bullets with the base ground to an exact angle. When fired the point of impact could be calculated and controlled based on that angle.

Since a bullet is steered from its base when you check a bullet you are doing the same thing, determining the angle of the base. If your check is not perfectly flat, round, perpendicular and obviously stay in place then your accuracy is going to vary, simple as that. PC just assures the check is bonded in place.

[curator]

Push-through boolit sizing dies often result in the gas check not getting crimped on solidly against the bullet base. The cure for this is to size your boolits first "nose-first" then install the gas check and size base first. Works for me every time!