Are Gas Checks A "MUST" For Bullets Over 1500 FPS?

[shotstring]

I've read and read and read....and most feel anything over 1500 fps requires a gas check, and some put that figure much closer to 1000 fps. Others however, say they have driven cast rifle bullets up to and even over 2000 fps with the proper alloy and the proper size bullet.

I have a setup to reload cartridges with cast bullets at 45-70 velocities without gas checks, but I wish to purchase a 500 gr mold that will cast bullets that will be driven at closer to 2000 fps in my 458 win mag. Do I really need to get a mold with a gas check?
Gas checks just kind of rub me the wrong way....go against most of the things I am trying to accomplish by casting bullets rather than using jacketed, so I would sure prefer to go with a plain flat base.

[44man]

I have gone to 1800 fps in my BFR revolver using a pb boolit. It has only been the alloy or fit that has given me any leading to speak of. I don't know if there is a limit.

[Ricochet]

Depends on a lot of variables, probably not all readily identifiable, but including bore condition, alloy, sizing, lubricant, powder, pressure...

[Bret4207]

Real simple answer-"MAYBE". There are a million variables that prevent anyone from making a blanket statement IMO. I know you can get up around 1500 fps in some gun/load/alloy/design combos. Others lead at 1100fps. My gut tells me you need a medium alloy-WW- that is as fat as the chamber will take and a moderately slow powder. It's all about fit at first. Lube isn't the huge issue some make it out to be. IOW- there are great lubes, but none cure everything. You have to experiment a bit to find what will or won't work in your gun. IIRC the 458 is to be treated pretty much like a straight walled case, an overgrown 45-70. Satrt from there and see where you can go.

[JeffinNZ]

Nope, but I do use a .060 card wad under my PB 300gr bullet in my .38-303 for 1700fps.

[Lloyd Smale]

my new 475 lever gun has seen about 2000 rounds of 360s at 1650 in the last two weeks and its a plain based bullet. The bore looks as shiny as day one. No lead whatsoever. Im shooting a bullet that is cast out of #2 which is actually a little softer then i would normaly try. I had a bucket of them i wanted to use up before i switched to 5050 ww/lyno. But found out the #2 is just fine in this gun. Alot of it has to do with the quality of your barrel, bullet fit, alloy and lube. Ive also seen 6 guns that would lead badly at 1100 fps without a gas check. But usually theres problems with a gun like that and even a gas check isnt a cure its just a patch. What i have noticed over the years is for the most part, and there is some exceptions, a gas checked bullet will normally shoot better at velocitys over 1400 fps then a plain based bullet will. But that cant be a cut and dried comment either because it could be that the gas checked bullet is just a better designed bullet then the plain base im comparing it to. About all a guy can do is spend time at the range with your specific gun and find out. Its about like asking what the best load for your gun is. EVERY GUN IS DIFFERENT.

[44man]

Yep, thats the total answer, you have to try what you have.

[Bent Ramrod]

It seems to me it's sort of related to boolit diameter. For me it starts about .32 caliber. Unless it's a small cartridge, like a .25-20 or .32-20, gas checks seem to be more necessary for the average sized cartridge case. .30 calibers like 311241 and 311274 have to be kept slow, while 311291 can be sent down there pretty quickly. Certain .32's like 321232 don't seem to give trouble, although 319241 has to be kept a little slower. At .35 caliber (in a rifle) there is no trouble I've found and by the time .44 and .45 is reached, a gas check is pretty optional.

I don't shoot extremely slow powders; generally 4198 to 4895 is my lower limit to powder speed, so this may be a factor.

[longbow]

I used to have a custom Mauser 98 converted from 8x57 rimmed to .45-70 and with a 26" tube. I used to load plain base ACWW boolits to jacketed bullet velocities using Hornady's Ruger info so pretty high pressure.

Boolits were Lyman 385 gr. round nose, 405 gr. flatpoint and 500 gr. round nose.

Used Valvoline PB wheel bearing grease for lube smeared on by hand on unsized boolits and only got leading in the last 2" or 3" of barrel until I put a .410 fiber wad between the powder and boolit base, then no leading.

According to my current Hornady book a 350 gr. round nose "J" bullet out of a 22" barrel reaches 2200 FPS and a 500 gr. 1800 FPS. I did not have a chronograph (or sizer luber) in those days ~ spent my money on the gun and cast boolits so I could afford to shoot it. So I can't verify velocities but they should be close to the book velocities especially out of the 26" barrel.

I also had a Marlin 1895 straight grip with 5 shot half length mag and normally shot the 385 gr. round nose in that. Hornady shows 1900 FPS for 350 gr. "J" bullet out of a Marlin so still pretty potent ~ no leading.

So with unsized ACWW boolits lubed with wheelbearing grease and reaching velocities in the 1800 to 2000 FPS range I got good accuracy and no leading.

I never shot in matches but we used to set up balloons at 300 yards and we could all regularly pop them with the Mauser and Williams peeps, no scope. Everyone who shot the gun was amazed at its accuracy... and recoil! Good enough accuracy for me anyway. A little much recoil with those loads but accurate.

Offhand with the Marlin it was hard to miss a 12" gong at 200 yards.

Unfortunately I sold both guns (and several others) to help pay college tuition several years later. I still miss both those guns. At least I am smarter... well, maybe not, someone else has those guns now!

[shotstring]

Selling guns to get smarter. I think we have a definite oxymoron here. :-?

[Ricochet]

Used Valvoline PB wheel bearing grease for lube smeared on by hand on unsized boolits and only got leading in the last 2" or 3" of barrel until I put a .410 fiber wad between the powder and boolit base, then no leading.
I used to lube that way with wheel bearing grease, till I realized that if I didn't shoot them quickly after loading I got extreme velocity variations, squibs and once a stuck bullet from the oil that seeped out of the wheel bearing grease and infiltrated into the powder. Only took a few days to start.

[longbow]

Ricochet:

I guess I can't really speak to that one either since I had limited brass supply and tended to load then shoot within a day or two - generally a couple hundred rounds went to the range for a day of fun. That and a muzzleloader or two and .22's etc.

I will say that the Valvoline PB wheelbearing grease was very thick and "stringy", and did not "bleed" oil like the wheel bearing grease I have now ~ which by the way is used for wheel bearings. I normally lube boolits with a melted mix of Lee LLA and a little paraffin to thicken it. Just dip lube 'em to fill the grooves. Crude but it works for me and isn't as messy as tumble lubing.

[DonH]

There are obviously no hard and fast rules on this. I have less experience with gas checks than with plain-base bullets. I shoot lead/tin alloy bullets from a .32-40 into the 1400 - 1500 fps range with fairly fast burning powders (H108, 4227) with no leading. Aloys have ranged from 1-20 to 1-30. I have overheard shooters speak of going as high as 1700fps with similar alloys with no leading albeit with less accuracy than at lower velocities. As for lubes, a firing-line full of guys shooting the same set-up will achieve similar results in their barrels and on target with a wide variety of lubes.
I will qualify the above by stating that my bullets are cast in amould cut to fit my barrel/throat and shot unsized. My lube is pretty traditionsl mix of beeswax, tallow and oil with a bit of lanolin added.

[Sundogg1911]

I've shot .30 up near 2000 fps with no gas checks and no leading at all.....but then again. I shot some slow 9's from my Wifes carbine and had a total mess within 50 rounds. Ricochet and Lloyd hit it....too many variables and every gun is different. I'd say just try it, if you can afford a mould that may or may not work for your app. If you know of anyone that uses the mould that you're lookin' at, just ask 'em for a few to try. I've asked in a post if anyone had a certain mould or boolit on here and couldn't believe the guys that just sent me some. (ok....after being a member here for a while, I can believe it.) but someone probably can help you out.

[shotstring]

Thanks for all the replies and all the input. I will pick one of the mold types and play around with it for a while as was suggested. This bullet casting stuff is great, and I have saved so much money over jacketed with the purchase of each and every new mold that my wife has run out of expletives to describe the vision of my purchases. So she's not talking to me at all right now. :coffee:

Maybe I'll wait just a few weeks or so before adding another mold. [smilie=1: