Heat treating boolits

[Marlin Junky]

I wasn't sure where to place this post and I hope the experienced heat-treaters see it here.

I'm shooting a plain based .30 cal boolit from the 30WCF which is about 1.08" long with about 60% of its length as bearing surface. My 336A (old 24" model with a 10" twist) measures .310" in the grooves and about .3005" across the lands. The boolit drops from the mold at .3130" to .3135" in my alloy that registers 15 BHN on Lee's scale. After running through a polished .311" die the bullets wind up a pretty darn consistent .3115" over most of their bearing surface and they appear to be VERY round on their .120" long bases.

9.0 grains of Scot 453 sends these boolits down range at 1325+ fps. I chronographed two 15 round strings yesterday with the following results (bear with me, I'll get to the heat treating question in a minute):

Using Fed 210s, I got:

high: 1335
low: 1316
ave: 1325
std dev: 5.1

Using Fed 210Ms, I got:

high: 1341
low: 1323
ave: 1332
std dev: 6.3

I would assume the groups I shot with these loads would deliver accuracy as good as I can get with my gas checked ammunition that produces similar stats over the chronograph. Unfortunately, the accuracy is not happening and I have come to two conclusions. 1) My bullets are unstable because they're going too slow; or, 2) My bullets can't handle the pressure and the bases are getting distorted (I wasn't able to recover any). Obviously, the problem could be a combination of both hypotheses... or neither!... then I'm really up the creek.

OK now, when heat treating, what temperature do I use, for how long and will the boolit diameters change slightly? I have an old Lyman manual that I think covers heat treating (to a limited extent) but I was wondering if anything new has been learned in the 20 odd years since it was published. I'm pretty sure my alloy is nothing but clip-on wheel weights and solder. I'm pretty sure no extra antimony snuck into the batch of alloy in question.

I've tried to push these bullets faster to gain stabilization but all that did was enlarge the groups into patterns. My best guess at this point is the alloy is too soft for the pressures generated by the Scot 453, but this powder produces such nice results over the chronograph without filler that I want to continue working with it. The 5 shot groups from the 30 rounds shot above measure in the 2" to 3+" range at 75 yards on a calm day.

Thanks for your input,
MJ

[Wayne Smith]

Well, the first and easiest thing to try is to water drop them, seat the check and size and then wait a week or two. They will then be about a BHN 25-26 from what I've read here - don't have a hardness tester myself to confirm this. Push these a little faster. I doubt you have pressure problems unless that is a very fast powder.

Are you getting round holes in the target or oblong? A destabilized bullet will give you a slightly elongated to very elongated hole as the bullet is tipping as it goes through the paper.

Finally, at what range are you shooting. A bullet may not be stable at 25 yds and have stabilized at 50 or 100.

[Slowpoke]

I wasn't sure where to place this post and I hope the experienced heat-treaters see it here.

I'm shooting a plain based .30 cal boolit from the 30WCF which is about 1.08" long with about 60% of its length as bearing surface. My 336A (old 24" model with a 10" twist) measures .310" in the grooves and about .3005" across the lands. The boolit drops from the mold at .3130" to .3135" in my alloy that registers 15 BHN on Lee's scale. After running through a polished .311" die the bullets wind up a pretty darn consistent .3115" over most of their bearing surface and they appear to be VERY round on their .120" long bases.

9.0 grains of Scot 453 sends these boolits down range at 1325+ fps. I chronographed two 15 round strings yesterday with the following results (bear with me, I'll get to the heat treating question in a minute):

Using Fed 210s, I got:

high: 1335
low: 1316
ave: 1325
std dev: 5.1

Using Fed 210Ms, I got:

high: 1341
low: 1323
ave: 1332
std dev: 6.3

I would assume the groups I shot with these loads would deliver accuracy as good as I can get with my gas checked ammunition that produces similar stats over the chronograph. Unfortunately, the accuracy is not happening and I have come to two conclusions. 1) My bullets are unstable because they're going too slow; or, 2) My bullets can't handle the pressure and the bases are getting distorted (I wasn't able to recover any). Obviously, the problem could be a combination of both hypotheses... or neither!... then I'm really up the creek.

OK now, when heat treating, what temperature do I use, for how long and will the boolit diameters change slightly? I have an old Lyman manual that I think covers heat treating (to a limited extent) but I was wondering if anything new has been learned in the 20 odd years since it was published. I'm pretty sure my alloy is nothing but clip-on wheel weights and solder. I'm pretty sure no extra antimony snuck into the batch of alloy in question.

I've tried to push these bullets faster to gain stabilization but all that did was enlarge the groups into patterns. My best guess at this point is the alloy is too soft for the pressures generated by the Scot 453, but this powder produces such nice results over the chronograph without filler that I want to continue working with it. The 5 shot groups from the 30 rounds shot above measure in the 2" to 3+" range at 75 yards on a calm day.

Thanks for your input,
MJ

How did you decide on .311?

I would use the largest diameter that will chamber.

I would also fill the chamber neck with cartridge brass, meaning you might have to neck down some 38-55 or 32-40 to get the length you need.

I would also seat to the maximum OAL that your gun will tolerate and hopefully the nose diameter is capable of a getting a little guidance from the land tops.

If I still was unhappy I would move to a slower powder and start over.

If you want max hardness you will have to find the temp that your alloy slumps, should be upwards of 450* and then back off 15 *, i hold it at that temp for 1 hour, some get by with less time, say 30 to 45 min. and then quench fasssst. After heat treatment if they sit around for a few weeks or longer you might notice a little increase in diameter, at least that has been my experience.

Good luck

[Marlin Junky]

Slowpoke,

Thanks for the post. Actually, I decided on .3115" not .311". I agree that .3110" is too narrow for a plain base boolit assuming a .310" grooves. I was sizing to .312" in cases that I neck turned for uniformity and may go back to that diameter but will probably need to buy another .312" die. I think I may have a .312" die laying around that I did a crummy job of polishing out to .3125" and it's no longer round. Your heat treating procedure sounds like that published in my Lyman manual. So, you have noticed boolits growing slightly in diameter after heat treating... that sounds good. I'll try the heat treating method on about 50 and report back.

I believe I am seating to a depth (COL: 2.57+") where the front band is contacting the rifling. This boolit in question is being cast from a mold I designed to fit the rifle and I will scrutinize the spec's but it fits pretty darn good; which doesn't mean it couldn't have been made to fit better. I suppose one can always do a better job the second time out.

Thanks again for addressing my points of concern,
MJ

P.S. I just realized that my brass has been trimmed back to 2.025" so I'd have something to crimp on when loading RCBS-30-180FN to a COL of 2.570". Could that small gap between the mouth and chamber's end have something to do with poor accuracy?

[45 2.1]

You are attacking your problem in the wrong direction. I shoot plain based boolits in the 30-30 all the time at 1500 to 1650 fps with no problems whatsoever. DO NOT try for harder boolits. Cut your wheelweights about 30 % with very soft lead. Your sizing diameter is about perfect. Use a soft lube, Lyman blackpowder gold is good as are some others. Try about 10 to 10.5 gr of Unique. Stability is not a problem at the velocity you are shooting at, but hard boolit are.

[robertbank]

Lyman's Cast Book Handbook as a very good article on heat treating boolits which you might want to get your hands on. I found 10gr Unique to be ok as a plinking load out to around 50 yards but accuracy was OK but not exceptional. 34 Gr. of H4831 improved things a lot but powder is rather slow I think. My next loads will be with IMR 3031. I am shooting Lyman's 311041 GC boolits sized to .308.

Take Care

[SharpsShooter]

45 2.1 is on the right track. I shoot a 195gr Plain Base boolit just a bit over 1400fps and see groups of 1"-2" at 50yds with no problem using straight WW alloy. I size at .311 and lube with Bullshops #2 recipe. The powder of choice is Unique and CCI standard Rifle Primers. No filler needed. For these velocities heat treating is likely a waste of time.

[Slowpoke]

Slowpoke,


Thanks again for addressing my points of concern,
MJ

P.S. I just realized that my brass has been trimmed back to 2.025" so I'd have something to crimp on when loading RCBS-30-180FN to a COL of 2.570". Could that small gap between the mouth and chamber's end have something to do with poor accuracy?

Are you assuming your chamber length is to book length of 2.039 or there about's, or do you know your chamber length?

I have never seen your gun but I would not be surprised if a necked down 38-55 would slip right in with room to spare.

I am thinking you could have more than just a little gap and if so, yes it can make a differance on the target.

good luck

[Bass Ackward]

The problem with this sport is that there are so many ways to attack this. Rifling height is outstanding for soft metal. I would also question lube choice here.

[Marlin Junky]

I spent a couple hours pondering my dilemma this evening, decided that a harder boolit is a waste of time (I concur, 45-2.1) and now I can't sleep!

I have a question for those shooting PB boolits in the 30-30 and other necked cartridges. Are the bases of your boolits seated deeper than the neck/shoulder junctions? The base of my 197 grain, 1.08" long, plain base boolit is seated such that most of the .120" long base is below the neck. I don't think a boolit much softer than BHN 15 is in order here... but I could be wrong.

I am going to give this boolit another chance before I stock up on gas checks but this time I'm going for .312" diameter and Javelina lube instead of my home brewed, "high velocity" lube. I will use the same 9.0 grain charge of Scot 453 and test it against 10 grains of AA#5 which is the closest stuff I have to Unique.

Thanks to all for the input,
MJ

[45 2.1]

8 to 10 BHN is the range you want to be in. Get a pound of Unique and try it.