May be a silly question, but here goes. Why in reloading data do 225 gr. lead projectiles call for a gas check. (.44) 200 gr. does not, nor does 250 gr. I do not plan on using these for fast/hot loads. Thanks, Bob

That's just which bullet the data calls for. You can interchange plain base and gas check bullets for any normal use.

Ivan

Yep. Only need gas check bullets for hot loads.

In 44Mag,I used to shoot only GC in my max loads(aprox 1000/year).Last year,I was running low on GC and decided to try the rendering of Keith bullet as RCBS sees it(pretty far from the original design I might add).
It comes out at 255gr and on top of 22.3gr H110(safe in 2 of my 3 .44Mag so work up to it)the bullet is as accurate as my GC bullet and won't lead.
My next experiment will be to try my GC bullet(RCBS Silhouette)without the GC and see how it performs.I might end up not buying the little cupper cups anymore!
Qc

It's not calling for a gas check, just specifying that's the bullet they used.

__________________
Pisgah

Gas checks are all about protecting the bullet base from hot, expanding gases. Whether gas checks are used or not has nothing to do with bullet weight, but bullet speed.

The faster a lead bullet goes down a barrel, the greater chance of leading that leaves streaks of lead in the barrel. Mounting a copper "gas check" on the bullet base tends to counter any base metal "melting" that might occur during shooting, as well as "scrape" the rifling clean with each shot.

Generally, gas checks are used for bullets traveling in the transonic-to-supersonic range.