GC or flat base for rifle?

[Jim]

I'm gonna be helpin' a young fella learn to cast and load for his break open .44 Mag rifle. If I buy a new mold, should I figure on a gas check design or can shooting flat base boolits be done without a lot of problem in a rifle?

[leftiye]

Flat base will work. They have limits on velocity, but so does gas checked. That .44 can kick, and maybe he'd like a load for just shootin' in general. So, again, maybe non gas checked. A lot of the reduced loads people here shoot in 45-70. .375 H%H, 35 whelen, 06 etc can be equalled by a .44 mag in a long barrel easily. My .375 Imp. load is about equal to a .44.

[turbo1889]

Provided one uses a charge consisting of a large amount of slow burning powder as opposed to a smaller quantity of faster burning powder a plain base boolit works just fine in a 44-mag carbine rifle. In fact that is true with almost all small capacity compared to bore diameter cartridges in a long gun platform the vast majority of which are the various carbines designed to shoot cartridges normally used in handguns.

[MtGun44]

I shoot various plain based designs at full max loads in .357 and .44 mags, mostly pistols,
but some in the .44 Browning 92 carbine, too. With proper fit (groove +.002 or so) you will
do just fine. If it was a lever gun, the Keith designs often hang up due to shape and long
length, but some guns feed them fine. With the break open you'll be home free with about
anything, with the throat being the only possible issue.

I'd recommend the RCBS 44-250-K or H&G 503 or Lyman 429421. The std Keith load of
20-22 gr (start lower, please!) 2400 works great for me and most. H110/W296 loads are
also good. Do not use mag primers with 2400 to reduce fliers, but H110/W296 needs them.

Bill

[onondaga]

I have found that straight Wheel Weight alloy 250 gr bullet shoots great in my 500 S&W Mag Handi-rifle at 1885 fps. Adding some Linotype would likely bring up the velocity accuracy/ sweet spot also but my grandson shoots this rifle. I have heavier bullets for the rifle, but neither one of us likes them. My recommendation would be to choose a lighter bullet weight for the youngster and push it along fast instead of a heavy shoulder thumper. My stock on the Handi-rifle also has the hole in the butt stock weighted with a lead filled copper pipe.

The Lyman gas checked 210 gr flat nose 44 Mag bullet looks good. With a starting load of 26.4 gr H110 in the Lyman rifle data shows the gas check bullet getting 1929 fps. with #2 alloy. This will kick less than what my 115 lb grandson shoots.

The pressure and velocity are the limiting factors with plain base bullets in a rifle. A plain based bullet will gas jet when the load pressure exceeds the alloy strength. Lynam #2 alloy ultimate yield strength is 21,898 psi, gas jetting will start there so about 10% less is a good target for a load with accuracy and the velocity the #2 will handle at Max. You would have to search that out but I'd bet that would put the 200 gr Lee plain base bullet at about 1500 fps Maximum out of a rifle with the lowest pressure powder you could select.

The lighter 200ish grain bullets in a .44 mag rifle will have trajectories a lot flatter than the heavier bullets, And really for deer hunting, A 200 grain bullet is certainly not light.

gary

[runfiverun]

a 200 will do fine for most everything.
a good round nose flat point with a good sized lube groove is hard to beat in a rifle.
you will most likely find one in 240 grs though.
if you can keep good neck tension you can get away with no crimp and seat the boolit out a bit further.

[Harter66]

I have the good fortune of having a 38,357revolvers and a lever rifle that will share brass. For accurate shooting I actually shoot fairly "slow" loads in the 357s at about 1150fps in the revolver w/boolits that tip in 162gr. In the 18" rifle the same load clocks in at 1465fps. All I shoot at this time are PB boolits with Unique,Red Dot and H110. I'm sure I could "hop up" the loads as the revolver is built for the old 45000 psi standard,but it shoots better in the revolver. By good fortune what shoots best in the revolver shoots even better in the rifle. I've gotten my 06' up to 1800 w/ PB also.

[BOOM BOOM]

HI
I have had good luck with the Lyman 250gr. gc. Kieth in the 444 Marlin. Best cast rifle groups I ever shot. And with a ported lever action at that! They were squib loads.:Fire::Fire:

[HighHook]

I shoot 2 different loads. The PB Lyman Keith with 8 gr. Unique and an rcbs 240 GC with lots of 296 for the Thrill of owning a Magnum.

[turbo1889]

I'm sorry, onondaga, but I'm going to have to politely disagree with you. From what I can tell you are going straight with what Lee has to say about boolit hardness and pressure and the resulting accuracy/in-accuracy and leading/not-leading.

Yes, I agree with the basic principle that Lee tries to exactly quantify but it is not nearly that simple or so easily quantified and I have seen way too many loads including many of my own that absolutely break the Lee rules and shoot as good or even better then loads that strictly follow the Lee rules.

Not only that, but there is two hard science factors that the simple Lee formula do not take into account. First of all only the tiniest sliver off the very bottom of the boolit is actually subjected to compression and shear loads that equate to the full pressure of the load. In fact the very tip of the boolit has nearly no stress on it at all and the compression and shear loads the alloy of the boolit are exposed to vary continuously along the entire length of the boolit and also across its cross sections in a radial variation of the load as well from the center to the outer wall engaged with the rifling. Secondly, peak pressure merely equates to peak acceleration forces on the boolit and does not quantify the derivatives of acceleration which in physics is known as "jerk" or the rate of change of the acceleration which itself is in fact a derivative of velocity which is the rate of change of position. This second derivative of acceleration or the derivative of the pressure curve (the rate of change of the pressure curve - the shape of the pressure curve) is just as important if not more important in quantifying how well a boolit made of a particular alloy with or without a gas check including a full length gas check also known as a jacket will hold up in a load as the peak pressure and thus peak acceleration are. This is not a WAG statement but rather based upon the foundation of the hard science of basic physics, static engineering, dynamic engineering, and known properties of materials.

To go a step further: The yield strength of copper varies between 10,000 and 53,000 PSI depending on how much it is annealed or hardened. Do you think they draw copper jackets and make copper solid boolits out of the hardest copper possible or the softer annealed stuff ? If you don't know the answer to that question then drop by the swaging section of this forum and talk to some of the guys who swag their own bullets that are just like the jacketed boolits they sell in the stores only usually better in one way or another. So if one assumes a "really, really hard but not so hard as to be brittle" copper jacket material with an yield strength of 40,000 PSI Well then, I guess we need to remove all the loads in all the load books with pressures higher then that don't we? At the very least all those magnum loads that go up above 53,000 PSI are worthless with even copper jacketed bullets. Assuming of course that the Lee method is gospel truth and it really is that simple and easy to quantify.

[Jim]

Well, me thinks a flat base just might do fine for recreational shooting. Thank you all for your responses. I appreciate your feedback.

[Bret4207]

Not to be contrary but a GC ALWAYS makes things easier. Not better, not faster, not harder. Just easier.

[Jim]

Bret,
Teach me. I'm not a PhD in GCs. How does a GC design make things easier?
This is not a challenge, it's a request for education.

[excess650]

I'll agree with Bret that it will be easier starting out with a GC. That said, its certainly true that plainbase can and will work within certain velocity and pressure limits.

Plainbase will be less $ due to not needing gas checks. A flatbase would always be my preference over a bevel base, and it will teach him to work for perfectly sharp bases. The Lee 44-200RF will allow easy duplication of 44-40 loads. Recoil will be light.

If this barrel has shallow rifling, I would go straight to a GC design. You might also want to check the rifling twist. If its that goofy, slow 1-38" twist(ala 44-40) it will be more fussy about loads. Something in the 1-20" range would be more forgiving, IMO.

[HammerMTB]

Not to be contrary but a GC ALWAYS makes things easier. Not better, not faster, not harder. Just easier.

I have found the same thing. Loads that would have leaded or been from mildly to wildly inaccurate are tamed nicely with a GC. Inconsistencies in base are also cleaned up.
I have and shoot some PB .44 boolits, but the GC'd versions of same are easier to build and use with success.

[rintinglen]

I have to agree with Bret on this one. It is easier to get good groups with a gas check design than it is with a plain base boolit, especially if you are using boolit metal of unknown composition. This is because you are removing some of the effects of variables in metal strength, diameter after sizing, and so on. I have a 44 Marlin Cowboy that does just fine with darn near any thing I put under a 429-244 Gas check bullet. I have yet to find a load that will shoot really well using a plain base boolit. (Though that doesn't stop me from looking--there is a box of 429-421s under the bench right now waiting for some work with 5744--a powder I hadn't thought to try, but which a friend recommended).
That said, many people can and do shoot excellent groups with plain base boolits, I would recommend the RCBS version of the 250 Keith bullet for a plain base boolit, or else a Lyman (preferably one marked Ideal) 429-215 for a gas check design.

[Bret4207]

Jim, in the simplest terms a GC provides a stronger base with the ability to retard gas pressures and scrape any accumulation of alloy from previous shots. A noobie may fail to discern the difference between a completely filled base and an almost perfect base, the GC can help there too by providing a consistent base if properly applied.

Any PB, IMO, is dependent on better than average fit, fillout, overall quality control and pressure balance for good shooting. I'm not saying it's impossible for a noob to see success with a PB righ toff the bat, but discouragement is just as likely, especially if they follow the normal course of starting off quite a little bit hotter than most here would recommend.

Just my contrarian opinion based on multiple failures early on.

[onondaga]

Your science certainly makes some sense, but the Lee theory has repeatedly verified itself also in my testing and I believe it is just as reasonable to recommend and much less complex.

Gary

[turbo1889]

I used to take the Lee formula for gospel truth as well until I learned better. I'm not saying it doesn’t work. In fact I will say that it does indeed work and is much better then the old velocity rule of thumb method. I have just found that it assumes the absolute worst case scenario which in reality is an unrealistic scenario and thus ultimately is too conservative for almost all loads and suggests the use of harder then necessary alloys in many cases.

Two excellent examples: 38-spl PB wad cutter loads using pure lead with just a dash of tin that is in the 7 BHN range, according to the Lee method 15-K pressure range loads should be way too much pressure for that load and the alloy should be way too soft. In reality that is just right and makes for superb loads that shoot with extreme accuracy and leave a beautiful clean shinny barrel. 7x57 PB cast boolit loads using WW alloy plus a dash of tin water dropped to about the 20 BHN range, according to the Lee method loads operating at pressure levels of about 37-K should be way too much for the boolit to withstand and shoot accurately. But I have found that provided the pressure curve of the burn is a gentle curve they shoot nice and tight with only the slightest dusting of lead in the bore after several boxes of rounds that comes out with one swipe of the brush and three patches, the last patch being the oil patch.

In conclusion, I would say from my own experience and knowledge, limited as it may be, that one can use loads between 100% and 150% of what the Lee method would suggest is the absolute maximum pressure for a given alloy hardness dependent upon the pressure curve shape of the load one uses. With a very aggressive and extremely fast burning powder curve that "spikes" almost immediately after ignition, then yes the numbers that the Lee method suggests is correct. Tame that curve down though and you can get more and more out of the load working far beyond what the Lee method suggests. Throw a gas checked boolit into the equation and you can push it well beyond the 150% mark, or better yet in my mind use a softer alloy at the same pressure with the addition of a gas check. Velocity is a factor as well, mainly due to rifling twist stress on the boolit and gyro forces on an imperfect cast boolit which rarely has a truly axial center of gravity like a quality match grade jacketed or copper/brass/bronze monolithic solid bullet has. My point is that all the derivatives play a roll, the first derivative velocity, the second derivative acceleration (usually we reference the peak pressure responsible for the acceleration rather then the acceleration directly), and the third derivative "jerk" (usually we reference the powder burn curve shape responsible for the "jerk" rather then the "jerk" directly). They all play a part, granted the second derivative appears to be the dominate factor and the Lee method rightly recognizes this but the first and third derivatives modify the equation further and need to be considered as well to obtain the full picture.

As far as gas checks go (back to the original question by the original poster). Yes, for a beginner a GC boolit would probably be easier to just jump into and go. Ultimately though, it isn't necessary for the gun we are talking about provided the rifling isn't something weird like that stupid micro groove rifling.

[MtGun44]

"Lyman 250gr. gc. Kieth " - there is no such thing as a "GC Keith". Elmer was very
allergic to GCs, AFAIK never designed a boolit with a GC. My guess is you are thinking
of the 250 GC Thompson design which many folks like a lot.

My personal experience has been poor to avg with this design (429244/430244), but
clearly I am an unusual example with this design.


Bill

[mpmarty]

Heck and tarnation!! My micro-groove barrel eats plain base boolits just fine in my 45/70 at velocities around 1500fps which is all I want or need. No leading and accuracy is fine since I mounted a 1.5 X 6 scope to compensate for my seventy year old eyes.

[turbo1889]

Bret,
Teach me. I'm not a PhD in GCs. How does a GC design make things easier?
This is not a challenge, it's a request for education.

The part of a boolit that experiences the highest stress loads is the very bottom base and especially the bottom perimeter edge around the bottom driving band. It has the high pressure gasses like a cutting torch trying to leak around the bottom edge and a massive torque load as well. From an engineering point of view the gas check is a case of nearly pure elegant simplicity; it puts a harder stronger metal that is more resistant to gas cutting exactly where it is needed most and no-where else. You may have heard the joke about engineers that the glass is neither half full nor half empty but rather the glass is twice as large as it needs to be to do its job. The gas check is the glass that is the right size for a certain class of loads that go above and beyond what a plain base boolit is able to withstand but where a full length jacket is unnecessary.

Just like a jacketed boolit is more forgiving to how it is loaded then cast boolits in general. A gas checked cast boolit is more forgiving then a plain base boolit do to its copper clad bottom. Which isn't so much a matter of the bottom of the boolit being protected by a copper base as having a copper ring for the bottom driving band. In fact so long as one can securely attach it to the base of a boolit so that it does not come off the boolit in the bore a copper ring or washer works just as well as a gas check. There were even a few molds made back in the day that were designed to use zinc washers on their base instead of a regular gas check.

For the particular combination under discussion namely the 44-mag cartridge in a long gun firearm I personally don't think you need either a gas checked boolit or a jacketed boolit since with the proper choice of powders and casting alloy you can get everything performance wise out of that combination with a plain base boolit that you can with a gas checked boolit or a jacketed bullet. That is my personal opinion, however, with a gas checked boolit you won't need to be as picky about your load. Of course if one follows that logic to its conclusion a jacketed bullet would be the best choice since it one can be even less picky about the load used then.



As to micro groove barrels; I personally have had no luck with them with either plain base or gas checked and would seriously consider not buying a gun with either micro groove or polygonal rifling or if I did switch out the barrel for the correct type of rifling ASAP. Others mileage may vary.

[1Shirt]

I don't get all excited about theories, formulas, etc. I cast hard, water drop everything for conveniende, cast/size and lube large to insure proper fit, and have had no problem with 44 or 357 from rifle w/plain base. If it works, I tend not to try to fix it. If it shoots well, and doesn't lead, think I it is satisfactory. I like GC blts, and I like the Thompsons as well, but I like the proper sized plain base just as well from a cost standpoint and convenience factor. More or less the KISS principle. Just my opinion.
1Shirt!:coffee: