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mikenbarb
11-20-2008, 11:08 PM
Im wondering what tricks or secret lead alloys and lube there are for meeting or exceding the 3000fps mark with cast boolits out of a 300Win.Mag.? Im reaching the 2600fps mark but starting to have problems with leading and accuracy. I know, I know. Why push it?, Because I want to see if I can get any decent accuracy at that level of velocity. Im not a speed freak but it would be nice to have a load for that velocity if possible.

felix
11-20-2008, 11:14 PM
Mike, increase velocity to 32-3300 and the leading will go away. Mashing the boolit pronto into the barrel is the secret. Barrel must be smooth and have enough lube. Boolit might be destroyed in the process, and you'd be lucky to hit a barn with that 10 twist. ... felix

smokemjoe
11-21-2008, 12:24 AM
I been shooting my 30 BR 1-14 twist, with 110 gr. bullet and 30 grs. H322 at 2745 fps. no -leading. but only 1.500 groups. Joe

Bullshop
11-21-2008, 02:21 AM
There is a way to go over 4000 fps with good accuracy. Think sabot.
BIC/BS

Larry Gibson
11-21-2008, 02:36 PM
mikenbarb

Sabot and PPing are ways to do it but I've only gone there with PPing. There are more knowledgeable people on the PP forum to explain that. However, if you are talking a regualr old cast bullet then; can we talk?

First off, 3000 fps with the .300 is easy. Doing it without leading and with any semblance of accuracy is another story. You must define "accuracy". Does it mean 1 moa, 2 mo with 3 or 5 shot groups? Does it mean just hitting the paper? Lets just say for sake of discussion that you want to be able to shoot 5 shots into 2 moa at 100 yards on demand any time you want to...is that to small? Knowing that let me tell you right up front the odds of you doing that are not good. It is tricky enough to get a 10" twist barrel to do that at 2300 fps let alone at 3000+ fps. If you want to know why you can read the several threads on RPM or PM me.

Assuming you want to attempt this with the rifle you have with it as is without rebarreling, rethroating, rechambering, etc. However, the barrel must be smooth. Firelapping may be necessary.

Let's talk bullet design. The bullet needs to be one diameter at not more than .001" (preferably .0005") smaller than the throat (leade) into the rifling. The length should be so that when the bottom of the GC is even with the bottom of the case neck the shoulder just touches the leade (rifling). It should have 2 lube groves abut .07" wide and .02" deep and a scrape/lube groove ahead of the GC at .02 after the GC is seated. The nose should not be over 1 caliber in length. LBT has a couple .30 cal moulds that fit this design. The mould should drop the bullets with your chosen alloy at not more than .001" over the throat diameter leaving sizing to .0015 at max. The idea is to have the bullet fit perfectly in the cartridge case neck and the chamber/leade throat right up to the rifling with no bore riding nose.

Let’s talk Bullet alloy. At that velocity with it’s attendant pressure and acceleration rate a hard alloy will be necessary. I’d suggest trying linotype and then a copper/lead babbit alloy. The copper/tin babbit alloy can solder to the mould at the high temp required to cast so it may not work.

Let’s talk gas checks. These must be quality and uniform. Hornady’s are the game here. You may want to anneal them and make a punch to insert into the annealed GC with it on a smooth steel surface and tap the punch. This is to give the GC a flat bottom.

Let’s talk bullet lube. The high end harder wax types are the chosen ones here. LBT Blue, Carnauba Red and 2700+ are ones to start with. You are still probably going to want to clean the barrel between groups to prevent leading and fouling build up.

Let’s talk powders. You will want to use the slowest burning powders that will give you the velocity wanted at 95-100% loading density. A chronograph will be necessary to check the velocity and also to tell you if the ignition is consistent. Look for an extreme velocity spread of 50 fps or less with your 5 shot test strings. This tells you that ignition is consistent and so is acceleration. Start with a slow burning powder and if it, at 100% loading density doesn’t give you the velocity wanted then switch to a slightly faster burning powder. Stick with extruded powders as some slow burning ball powders do not give good ignition until high pressures are achieved. Notice I only refer to consistent velocity here. Accuracy may be something else. Once you isolate several powders that give you consistent ignition and the required velocity at 3000+ fps with 95-100% loading density then you can maybe (that is a BIG maybe) tweak the accuracy.

Let’s talk primers. Many say when pushing into high velocity that using a softer primer “softens” ignition and increases accuracy. It generally does that but it also most often drops the velocity back down into a more accurate range. If we increase the velocity back up to where it was with a “harder” primer by adding more powder over that “softer” primer we find accuracy not to have changed. We just need more powder to get the same velocity and the same lessoned accuracy. Since you are using a larger case and slower powders I’ll suggest you test both the Remington 9 1/2 and the Winchester WLR with the first slow powder tested. The one that gives the best consistent ignition is the one I’d continue the tests with.

Let’s talk cases. Your chosen cases should be all of the same make and the same lot. They should be “match prepped”; trimmed to uniform length, flash holes uniformed and deburred and they should be fire formed. Neck sizing only should be done. I’d suggest a Redding Bushing die and several bushings .001” apart so you can vary the neck tension on the bullet from .001 to .003”. Use a .30 M-die or the Lee expander to bell the case mouths for seating the cast bullets. A Redding, Forster/Bonanza or RCBS precision seating die should also be used. A run out gauge should be used as bullet run out should not exceed .001”. Obviously an inside or outside precision neck turner is needed. Cases should be thoroughly cleaned, inspected and primer pockets cleaned before each loading. A clean .30 cal bore brush should be run through the neck to remove any carbon deposits or debris also.

Not exactly your normal cast bullet loading, eh? Well if you are going to dance you have to pay the band. I wish you luck in this endeavor. If you precede please keep us informed of your progress. I’ll be glad to answer any questions or make suggestions along the way.

The first suggestion I’ll make is to get a 16 or 18” twist barrel of 26-28” length. That will give the best chance of succes as you will be controlling the RPM. But that’s probably not what you want to do at this stage. Good luck.

Larry Gibson

Larry Gibson
11-21-2008, 02:41 PM
smokemjoe

Which 110 gr cast bullet?

Larry Gibson

mikenbarb
11-21-2008, 04:13 PM
Larry, Thank you for the wealth of knowledge. The gun has been rebarreled with a Shilene 1-12 twist and im currently working on a powder and lube that will give me what I want from it. I am expecting to obtain 3000fps with 1-2moa @100yds because im currently getting those results with velocities up to 2450fps. but jump up to 4moa as soon as I hit 2590+fps. I am using lino type lead and a babbit alloy with custom GC's that are from R.W. Kampen made a long ago(1940's) and their as perfect as they come. My boolits are all uniform within .001 and try for at least .003 or better and others get put aside for plinking rounds. I use one 10 pound lot for each batch of test boolits I shoot and if its a good lot I use it and if not it goes back in for furthur mixing till I get what I want. For my BR loads I use only Norma brass prepped and sized with competition series dies and prepped and handled as all my BR loads are and I try to maintain extreme tolerances with them all. Im fairly new to casting BR loads but im a mid to lower high scale LRBR shooter when im shooting jacketed bullets(The easy ones) but this is a whole new world to me. I have invested thousands upon thousands of dollars in quality equipment so poor equipment isnt the problem, Its the loose nut behind the wheel.LOL. Im working on a couple more loads to test tommorow and will post the results when I get back from the range.:-D

Larry Gibson
11-21-2008, 07:02 PM
You're not necesarily the "loose nut". Looks like you done your homework and are well on the way. With the loading technique you're doing looks like you're already pushing the RPM threshold up to 147,000 RPM at 2450 fps. The 2590 fps load is cranking 155,400 and obviously the RPM is getting to your bullet.

What bullet? What load is giving the 2450 fps accuracy? What loads are you testing tomorrow. We need to see what you can do to lesson any imbalances in the bullet to negate some of the RPM adverse affect.

Larry Gibson