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Thread: Gas Check Boolits without Gas checks ???

  1. #121
    Boolit Buddy

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    Being a geek myself, I was sad to see stephen and popper stop posting in this thread......
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  2. #122
    Boolit Buddy
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    I have not seen much discussion of systematic approach to "no-check" shooting with PC to get decent velocities without the check.

    This year, I started PC and now have 3 gas check molds


    • C358-200-RF
    • C309-150-F
    • C309-170-F


    I have been working the 308 stuff up for 30 Herret (10" TC & 14" TC), the 357 will be for 357 Maximum (8" DW & 10" TC).

    All without checks. Most with straight wheelweights.

    Just started on the 358-200-RF. Pushed it pretty hard and it seems shoots as good as any flat base has.

    I have done quite a bit with the 30H. So far, if I push too hard the accuracy goes out the door. With moderate loads, accuracy is as good as I have been able to get with cast bullets. I probably could do better on velocity with some babbit mixed in (for Cu) but have not been willing to buy the babbit. Velocities look good enough for for my goa (I hope to get back into IHMSA some day).

    Any pushing the "no check" option with PC?

  3. #123
    Boolit Grand Master popper's Avatar
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    I I'd test a couple years age, GC/sans GC in 30/30. With the alloy I was using and 2400, unique and LeverE, no check limit seems to be 1600 or so. ESPC of course. I've gotten to 1800 modified PB, PC before accuracy losses. I've got an alloy now with ~34 BHN to test, I'll try sans GC in 308. It's 2% tin by weight, replaced by Cu so 2% Cu, heat treated, ~4% Sb. Results in copper thread.
    Edit: Larry G's XCB tests, where GC fell off during firing, provide evidence it is the pressure related heat/weakening of the alloy, not flame temp that destroys the base. As I commented earlier, it means the shank gets rivited on firing that destroys accuracy. Additional evidence from my modified PB boolit ( really short GC shank) the pressure related soft alloy base deforms at the crown and accuracy suffers. Got to cast some for the BO with this hard alloy to see if the accuracy improves past 1800 fps. Of course it doesn't 'bump up' to seal very well so I get to try with various sizings also.
    Last edited by popper; 08-17-2015 at 11:08 AM.
    Whatever!

  4. #124
    Boolit Buddy Doggonekid's Avatar
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    I just got in a new boolit mold from RCBS. It is a 300 GR SWC .452 GC. I casted up a few rounds tonight. I want to run them through my .460 Mag. I will run them with GC and with out. I also will PC with GC and with out. Once I have some results that work for me I will post again on this tread. I'm not expecting a huge difference either way. I do expect some difference I'm just not sure how much. All of my other guns GC or not does not seam to make a difference. I just plink at soda cans from 25 to 50 yards. I like the option of having a GC mold. I can put one on or not. Non GC molds I have no option. The faster the boolit the more I try to get GC molds.
    "Life is tough, but it's tougher when you're stupid." John Wayne

  5. #125
    Boolit Buddy
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    Quote Originally Posted by Oyeboten View Post
    So...what ever happened to progressive Rifleing?


    I heard the Colt Dragoons had it...various Rifles of course did back when.


    What about now?


    All these 'skidding' woes could become a thing of the ( recent) past!

    ****, that's a good question, worthy of reply from some barrel makers.

  6. #126
    Boolit Buddy
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    I finally reached "happy" with my PC coated Lee C358-200-RF as checkless. Sub 3 MOA and around 1500 fps from a TC 10" 357 maximum barrel.


    http://castboolits.gunloads.com/show...27#post3459027

  7. #127
    Boolit Bub natty bumpo's Avatar
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    Quote Originally Posted by XWrench3 View Post
    i am certainly no expert, in fact, this post will certainly show how little i really understand about these. but i always thought that gas checks should be doubled up. like welded together, back to back. one side crimped on like they do, the other side facing backwards so they would act like a bevel base bullet. sealing all of the gas pressure behind the bullet. kind of like this.... ><bullet
    GENIUS !!!! (bear in mind that I am a complete moron when it comes to these things) BUT GENIUS !!

  8. #128
    Quote Originally Posted by Fire_stick View Post
    If your bullet is sized properly for your gun,
    and if the pressure is sufficient to obturate the bullet per the bullet hardness.

    Is there a need for a gas check? Even at elevated velocities?

    From what I have been reading, I suspect the answer is, or could be no.

    Although I also suspect powder burn rates may play a role in determining whether a GC is needed. Maybe it is simpler to use a GC and not worry with all the variables.

    Please help me understand.
    I have somewhat limited experience shooting gas checked bullets, and still have a lot to learn. I've used 1000 of each in 44 and in 35, plus several hundred in 38-55.

    Using a gas checked bullet can increase the flexibility of a load. I had 3 Vaqueros in 44 mag and a '92 SRC in it as well. Typical for production revolvers, the throats and groove diameters varied considerably. Rather than load 3 or perhaps 4 different loads, I found a load, with a gas checked bullet, that would work in all of them. Actually, one of the Vaqueros was not close in size to the other 2, so rather than facing the challenge, I sold it.

    Almost the same story with my 2 357 Magnums, rather than having 2 different batches of ammo, I use a 358156 load that works in both. One of the guns, a New BlackHawk will shoot well with any decent load. However, the other, a Colt New Frontier, Gen II, doesn't seem to like anything but a 358156 gas checked bullet.

    I've found hat a gas checked bullet will still work well even if it is undersize for the throats of the cylinder. Whereas a plain base one appears to work best at or larger than the throat.

    Playing with hardness and pressure is almost a "Mug's Game" IMO. Lead alloy bullets mostly harden with age, some soften. Powders burn at different rates, and the pressure curves can vary, and sometimes a higher "peak" pressure load, may not obturate enough to seal the throats, but a lower "peak" pressure load will. Alliant 2400 is about the most forgiving powder I have used, in the 44 and 357 Mags. If given half a chance it will work well with plain base bullets. Ideally a load, to be considered a good load, should work well within a range of powder charges, bullet hardness and size.

    I've concluded that gas checks are useful, especially for a beginner, as good results can be obtained easier and sooner with gas checked bullet than with a plain base design. The same can be said for PC (Powder Coated) bullets. Different theory, similar results. A gas check limits the effect of blow-by, less spray welding of the forcing cone, helps the bullet follow the rifling and tends to clean the bore of lead. Hardening, heat treating, cast bullets works as well, another useful tool.

    I think you already have a good understanding of what is required, "sized properly", "pressure is sufficient", and "powder burn rate" are all important factors. And "Maybe it is simpler to use a GC and not worry with all the variables." is precisely what my experience tells me.

    Using a gas checked bullet allows me to use the same bullet for revolver and rifle, in a range of velocities from 900 to 1600 fps, and in revolvers with 430 > 432 throats and 428 > 4295 grooves, and in a rifle with a bore/groove that I haven't bothered to check.

    I still experiment, with different loads, with different gas checked and plain based bullets, with some success. But I do have one load that will work well in all. BTW, the bullet that I use is a Lyman 429434, a mold designed for the 44-40 rifle.


  9. #129
    Quote Originally Posted by MT Gianni View Post
    Very interesting explanation.I have examined many hundreds of range pick up bullets, my own, others and commercial. I have never seen evidence of a melted base. The milliseconds that the temperature is there is not enough to melt them or most commercial lubes. Nor will the powder flame melt lead fouling.
    Thanks for your insight on the equations of a booits stress.
    I have picked up quite a few bullets that had lead missing from the base. Blow-by will melt lead. Blow-by will melt as the velocity significantly increases the temperature of the powder flame. That is why sealing is so important. I have an automotive engine background, poorly sealing piston rings will lead to blow-by, and although combustion temperature is below 1200 deg F, blow-by will melt aluminum pistons and burn moly and stainless rings.

    Something to try, Take a deep breath, now blow it out with your lips sealed as tight as you can, when your breath rushes out it will burn your lips. Yet your breath is not of hot enough to do that. The wings and the airplane flying at Mach will get hot, even in near freezing air. A meteorite will burn up when entering the atmosphere, and Hornady discovered that ordinary plastic tiped bullets with melt with velocity. All physical facts.

    And unfortunately, powder flame doesn't seem to melt lead fouling, it just seems to solder on more lead.

  10. #130
    Boolit Master
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    That seems strange as the laws of physics tell us that as gas expands it cools. Likewise as gas is compressed it heats as when it strikes the wings of an airplane.

  11. #131
    At the moment, i don't shoot at really high velocities. But this is good for when ido

  12. #132
    The first thing at any and all velocities is the fit of the bullet to the bore. After that the variables increase with pressure and velocity. Out to fifteen yards for instance, a smoothbore can shoot small groups or scatter the bullets like a shotgun. It all goes back to the fact that each individual firearm id a law unto itself and shooters whorealize that fact also know that shooting naked lead with or without gas checks or paper patching are embarking on a quest or adventure or heartbreak when trying for ? Accuracy, velocity, or a properly musroomed hunting bullet or not.The Holy Grail in the case of each firearm. The right alloy, matched to the right powder, matched to the right velocity or pressure.
    The neverending story. I love it and thank my Creator for leaving this on the table for me. Now with the closing of the last US lead mine in Missouri, we rely on recycling, which has become a sometime thing. All part of life's equation I suppose making it harder to blend alloys if you are so inclined in the chase to make your firearm perform.
    It's a great game but we should all accept that its varied answers when found can and may change with each pull of the trigger.

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check