BHN as a Function of Boolit Velocity

[ejcrist]

I have a S&W 686 with an 8 3/8" barrel that I shoot the RCBS 38-150-SWC cast from straight WW over 14 grains of 2400. The velocity average is about 1,490 fps, and this load averages about 1.5" at 25 yards off a rest. This load is the most accurate of all I've tried thus far in this revolver. I've read where a lot of guys cast their boolits harder for 357 velocities in the 1,500 fps range, and a lot also use gas checks. I've never used gas checks and everything has been fine in my universe and I also haven't seen any evidence of leading with this load and firearm aside from a few small pieces here and there. I'm thinking about casting my next batch of boolits a little harder, like maybe using Lyman #2 formula, to see the result. Do you fella's think I should use a harder alloy and or gas checks at these speeds or is it normal to use straight WW's at ~ 1,500 fps? In reading Glen Fryxell's writings on the LASC website I believe he mentioned the use of gas checks above 1,400 fps and/or harder boolits. On one hand I'm thinking not to change anything since all seems well, but on the other it won't hurt to experiment to see if there's any improvement. Any opinions would be appreciated.

Thanks, Gene

[paul h]

I've learned a few things about casting my own bullets and handloading. The first thing is, there are no absolutes. The second thing is, if you find something that works, don't go to the extra effort of potentially making it not work. Hence, if the load is accurate and you aren't getting leading, smile and load up 1000 of them.

Now, after you've loaded up those 1000 rounds, then go about experimenting ;) To me gas checks provide a bit more flexibility with bullet alloy choice, but I've shot enough plain based and gas checked bullets through magnum revolvers to know there is no magic point at which they are required. My feelings about gas checks are they may not be needed, but I've never found them to hurt.

As far as harder alloys, I've shot lots and lots of bullets cast from ww's. I used to think magnum revolvers had to have very hard bullets for top accuracy and to prevent leading, but then I started reading about how Elmer used alloys we today consider medium hard and he was not one to back down on powder charges or velocities. So I started air cooling my coww bullets and low and behold they shot fine and I didn't see any significant issues with leading.

If you want to try harder cast bullets, I'd suggest just dropping them hot from the mold into one of these

http://www.harborfreight.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/i/m/image_7527.jpg

[Crusty Deary Ol'Coot]

Well, for the most part I use just plain old Wheel Weights and for a number of years I have quenched them in a bucket of cold water as was shown in the last post.

For my .357 and because I shoot a minimum of .357 level loads and mostly .38 level loads there is no need for a gas check.

Then as you will soon hear, cast bullet to bore fit is VERY important. Bigger is better in most cases.

From My 45/70, I shot and tested a bunch of cast and gas checked bullets well above 2000fps and as high as a bit above 2500fps. 355gr cast mostly of WW and water quenched.

My standard load in my 44 has been a 310gr cast at just over 1300fps. I use a gas check on this bullet, GC are used for more then just leading issues.

Get that size right and make sure your cylinder throats are not under sized and you should be good to go!

Crusty Deary Ol'Coot

[ejcrist]

Thanks for the info fella's. I've been reluctant to cast anything harder than ww or 16:1 because when I first got into casting a while back it was for a SBH and medium velocity loads using the 429421 over Blue Dot for around 1,300 fps (don't remember the charge without looking and I'm too lazy to look at the moment). I cast those boolits using #2 formula from the Lyman Handbook because everything I read in there indicated you should use a hard alloy. I made sure the boolits were around .001" over throat diameter but I still had an awful lot of leading in that revolver until I read Fryxell's and Keith's info and went with straight ww's, and then the leading mysteriously disappeared. Ever since then I worry when I hear about using harder alloys. As a general rule I'll start with ww's and take it from there. If all goes well I haven't changed anything with the alloy. Another reason I'm reluctant to cast hard is because I've been shooting flintlocks much longer than revolvers, and while those round balls are wrapped in a patch, they're still only soft lead moving along at a pretty good clip and they wouldn't work well any other way. So I'm not very confident a harder alloy would improve things much if at all but I'll test a few out just to see. I got to thinking about it again after reading Brian Pearce's article in the latest issue of Handloader where he used harder bullets in his 327 magnum tests for the higher velocity loads. I respect Brian's opinions but if I were him I believe I would've started with ww alloy or 16:1 and only used the harder boolits if I had problems. Of course the boolits he tested were commercially cast so I guess he didn't have a choice of softer alloys.

[Crusty Deary Ol'Coot]

Just as another thought,

Lets say the throats happened to be smaller then your bore. To prevent the leading, the bullets need to be a bit larger then the bore size.

Sooooo, if the throats are small, the bullets will be sized down during the bullet's passage through the throat and will then be undersized for the bore.

Therefore, the throat size needs to be correct for the bore size. Should the throat size be a bit large, at least it is not messing with your bullet to bore fit.

Then, in Brian's situation, using commercially cast bullets, the term, "Hard Cast" is a much over used term which can mean little to nothing ------UNLESS the manufacture also provides a hardness figure for their product.

I doubt your going to have bullets which are too hard, unless you really work at it, so I'd not over think or worry about it too any great degree. Tin only hardens to a lessor degree, so something with a good percentage of antimony would be added if a lot of increased hardness was desired.

I have water quenched for years using just clip on Wheel Weights and they work great for most handgun use. For my 45/70, I use an alloy of 50/50 - WW/lead which is water quenched and allowed to age a minimum of 7 days before use.

For other rifle fodder, I am starting with quenched WW and we'll see how that goes.

Crusty Deary Ol'Coot

[Hickok]

I use ACWW (+ tin) for everything. Like Paul said, back in my early days I thought you had to have extra hard metal like linotype for everything, because that was what the Lyman manual stated.

My problem in pre-internet days was I could not find any linotype metal in small town USA, so I used what I had, COWW. Worked for me then and still does today. Found out about adding some tin here, and it was a big help in casting nice filled out boolits.

I think your present load is excellent and I wouldn't change a thing.

My procedure for testing a load made with wheelweight metal is to load a number of rounds in increments of 1 grain or thereabouts, and then shoot to check for accuracy and/or leading. Groups will start to tighten up to a point, and then start to get larger. The best group without excessive leading (and pressure) is what I then use. The velocity, pressure, obturation, accuracy will all come together at a certain point. Going over that point, will show bad results on the target, and in the bore of the gun, and can also lead to higher pressure.

I say you have reached the optimum point with your load, be happy!

[dubber123]

Been fooling with 50/50 WW-Pure, Bhn should be about 9, compared to about 14 for your air cooled WW's. I am using a GC boolit, but my velocity from a 9.5" F/A .357 is probably as fast as your load. No leading, last groups were .770" and .748" at 26 yards. I'm going to continue my experiments with the softer stuff too. Have fun.