375 H&H boolit diameter?

[Rickk]

I would like to use cast boolits in my .375 H&H rifle. I ordered a Lee mold but now am wondering if the .379 diameter is too large for this caliber? (Lee 379-250-RF)
I had hoped to shoot them without sizing using the Lee tumble lube alox. Help wanted!

[725]

I use that for a friend's .375 H&H. All rifles are different and you really need to slug the barrel to properly answer your question. I size to .377 for his. 13.5 unique makes a dandy plinker and small to medium game load. Hope he uses it on whitetail this year with the cast boolit.

[wmitty]

welcome aboard, Rick!

I haven't used the Lee mold but I would not be concerned as long as you can seat the boolets without shaving lead on the case necks. May need to bell the necks slightly more than normal. Also, have you slugged the bore on the .375? this is easily done with a fishing weight and a wood dowel. If you haven't got a mike, get a machinest to mike it for you and size the boolets to groove dia. or one or two thou. over groove dia. My model 70 mikes .377 as does my 700 Rem. Sure wish I could escape from north Texas to Alaska!

[Rickk]

Thank you both. I did as you suggested and slugged the bore. It measures .377. I will try casting some boolits using WW and see what the actual diameter turns out to be. If it is not over the stated .379 I will give them a try with a modest load such as you suggest.

[brian]

the throat on mine measures 0.381 if i recall correctly. Hmmm... maybe it was 0.383". none the less, slug the throat too, and size to the throat diameter to get best accuracy if you're going to push the speed at all. the bore diameter in mine is 0.377" which i thought was a little on the loose side, but from reading other postes here, not so uncommon methinks.
Brian

[Rickk]

I cast about 250 of the supposedly .379 bullets this morning. They turned out to be .377, and that only near the base. The rest of shank was closer to .375. (Using WW lead)

I coated them with Lee alox and hope to load and try them tomorrow.

Will try the 13.5 Unique load that 725 suggested.

[725]

Rickk,
My friend's H&H is a rebarreled Sako. I don't remember off hand what I slugged it out to be, but that 13.5 was one of the better performers. We went from 10.0 grains to ? I don't remember? -- something like 15 or 16, and clearly the 13.5 was best in his. YMMV

[Rickk]

Shot about 40 of the cast boolits today. Unique powder between 13-14 grains. Chrony was not working but Lyman manual suggests they were running in the 1300-1400fps range.

Best group was 3", lots of leading.

Boolits were tumble lubed with Lee alox, thinned with mineral spirits.

Tried hand-lubing some using rcbs lube, no better results.

Tried some that I had dipped in the alox and let dry base down, no better than the ones with the very thin alox coating.

I do not have a micrometer, but using a dial indicator it appears that the bullets are the same size as the soft round ball that I pushed through the bore, on my indicator it says .377 which jives with the comments above on other rifles.

Are the bullets just too small for the bore?
Do I need to push them a little harder to get them to obturate?

Previously the gun has shot only j____ boolits. Perhaps I did not do a good enough job cleaning the gilding metal from the grooves?

Suggestions appreciated.

[NuJudge]

I like cast bullets about .002" larger than groove diameter, if I can get them to chamber in a cartridge case. If your groove diameter is .377", as-cast .379" should be fine.

You mention using a dial indicator to measure the slug and your bullets. I believe you are describing a Vernier Caliper with a dial indicator. Test the accuracy of your measuring device by measuring several known quantities, such as .375" jacketed bullets.

I don't see the range you are shooting at, but if it is 100 yards, 3" is a decent sized group for no load development whatever.

If you are getting Leading, a variety of problems may exist. The groove diameter may be larger near the muzzle, the lube may have run out, the bullets may be soft, the lands and grooves could just be rough, and perhaps other things.

At the velocity you are shooting them, it should not take much of a lubricant to do the job. Can I suggest using a double coat of LLA?

Do you get a lot of copper fouling with jacketed bullets? If so, there may just be a lot of tool marks in the bore, which are going to cause a lot of Lead fouling too.

Regarding lubes, old reliable for me is the NRA formula of 50% Beeswax/50% Alox 2138F. You can get it from Lars at the link on the bottom. You can pan lube, to avoid the mess of finger lubing.

A harder cast bullet, or one with a gas check, may fix your problem with Leading. You might want to buy some cast bullets, or just ask for some hard cast, gas checked bullets in the forum here for that purpose. State the diameter you want. In the next few days I am going to cast a bunch of Lyman and other gas checked .375's, but I don't think they will drop at .379", closer to .377".

I hope this helps.

[Rickk]

Once again, thanks for the help. You are correct NuJudge, I have a vernier caliper with a dial indicator! Sorry for not speaking clearly.

I agree, the 3" group size is not that bad for no load development. (I should have stated it was 100 yards) If I can stop the leading I think we can shrink that down. The rifle will do 1.25 - 1.5" with jacketed bullets.

The jacketed bullets didn't seem to cause excessive copper fouling. I could see copper color in the grooves, but it didn't cause any problems.

I wish that the bullets would drop from the mold at .379 as the mold specs state. As best as I can measure they are .377 to .378, with the larger diameter at or near the seam. My measurement of the bore is .377. The alloy is straight wheel weights. I do not have easy access to tin or other materials.

I spent some time reading posts today and ended up doing a bit of work on the mold. I would like to try "beagling" but do not have access to the sticky tape the author used. (We live in bush Alaska)

I did do minor alignment of the handles so the blocks would close easier, and then lapped the cavities with a bullet and toothpaste as some had suggested. (hmmm, toothpaste in the cavities?)

No measurable change in diameter, and it took some time for the mold to start throwing good boolits again, but when the temperature of the blocks and the lead got up on the high end it started making nice looking boolits and they fell out of the mold much better. I had hoped the lapping and the higher temperature might cause the diameter to increase but it didn't. Still not completely round either.

Someone made a comment that the diameter of cast bullets may increase over time. Is that true?

I loaded another 20 rounds to try tomorrow. After the first 5, seated to the cannulure, I realized that given the short neck of the .375 the base of the boolits were considerably below the neck of the case. Could that be part of the leading problem? The remainder I seated so that the base of the boolit is even with the neck of the cartridge. They still feed ok and do not appear to be against the rifling.

10 were hand lubed with RCBS non-alox lube, the others were Lee Alox that had been hand dipped to the cannulure several days ago.

I did as you suggested and gave the remainder a second coat of Lee Alox.

I hope to try them tomorrow if the weather cooperates!

[looseprojectile]

I have been shooting my #1 Ruger with the Lee 270 grain flat nose boolit.
As it comes from Lee this mould has a bevel base. I straightened that out.
As it comes from Lee this mould is too small. I lapped it out to .381".
My #1 has the early Douglass barrel and slugs to .377". Size boolits to .380".
The reason I did this is so the boolit will thumb seat in a fired case.
That seems to take care of the fit in the chamber. There is very little boolit seat.
I have used Lee liquid Alox after thinning and also a coat of paste wax over that. Using a load of twentyone grains of SR 4759 and dacron filler I can shoot ten shots into less than an inch at a hundred yards. I know I know, you don't need filler with SR 4759.
This load gives me very near 1300 fps. My rifle has a Mag Na Ported barrel and I don't see any problem with the filler because of the porting. Nice it is there as I might load some full power bullet loads someday.
I have been using softer alloy and have experienced some leading with slightly faster loads.
Did you know that the 375 H&H case will easily hold ninety grains of FFG black powder? How about a 38-90 belted, or would that be regressing too much?

Life is good

[Rickk]

looseprojectile---I am very interested in any details you would provide as to the modifications you made to the mold.

I assume the lapping would be done with a number of boolits using progressively finer grit? From what I have read it must take several hours to accomplish the desired result?

I do not have access to a machine shop. Talk to me about removing the bevel. Why? Better accuracy? How?

[Larry Gibson]

Rickk

I wish that the bullets would drop from the mold at .379 as the mold specs state. As best as I can measure they are .377 to .378, with the larger diameter at or near the seam. My measurement of the bore is .377. The alloy is straight wheel weights. I do not have easy access to tin or other materials.

If you are using a bottom pour furnace then the problem may very well be the alloy is not getting into the mould quick enough. This often results in undersize bullets. Suggest you adjust the furnace for maximum pour or use a ladle. The object is to get the moulten alloy into the mould as quick as possible. Also casting hotter might help. You might also order some tin by mail. Adding 2% will improve the fillout in many mouldls and make most often produces better bullets that plain WWs.

I loaded another 20 rounds to try tomorrow. After the first 5, seated to the cannulure, I realized that given the short neck of the .375 the base of the boolits were considerably below the neck of the case. Could that be part of the leading problem? The remainder I seated so that the base of the boolit is even with the neck of the cartridge. They still feed ok and do not appear to be against the rifling.

Seating a PB below the case neck could very well be some of the leadin problem. Also I shoot a Lyman PB cast bullet in my .375 and find that 1400 fps is the ragged edge for accuracy and non-leading.

Larry Gibson

[looseprojectile]

What I am going to tell you is blasphemy.
When I have had a mould that needed to be several thousands larger I do a temporary fix like this.
You have the Lee mould and it is aluminum. Three or four strategically placed center punch marks beside the cavities will space the blocks further apart according to how much metal you displace. When and if you find that a larger boolit such as you will have with the punch marks works better you can carefully remove the punch divots with a stone and lap the mould cavities. I use an RCBS bullet puller collet to hold the boolit in the lathe and drill for a screw to spin the boolit in the mould with medium valve grinding compound. Make several, like three boolits with stems and check your progress at times by cleaning and casting a boolit to keep from getting it too large. I use a rechargeable drill to turn the laps. Variable speed.
I used a three eights outside diameter center drill to cut the bevel out of the mould on the drill press. then I smoothed it more with a fairly fine wet or dry sandpaper on a dowel. This is kind of touchy.
A man that lives in a remote area such as you do has got to be self sufficient.
I know that Buckshot, et al, are having coniptions about now so I will take my ball and go home. If you screw up your mould don't blame me.
Oh and welcome to to the site.

Life is good

[looseprojectile]

Sorry didn't answer your questions.
The sharper the base of the boolit the better. Bench rest shooters use flat base bullets and all the BPCR shooters I know strive for perfectly flat bases on their boolits. Works for me.
A couple of minutes with a lap has done all it can. Otherwise the lap becomes worn and not as precise. If all I had was coarse grinding compound I would use that as I have seen little difference between coarse and fine except the time it takes to do the job. A drill press is just a vertical lathe. I hope you at least have a drill press. Hang in there.

Life is good

[Rickk]

Larry and looseprojectile,

Thank you both for the comments-suggestions.

Yes I have been using a bottom-pour furnace. Normally I use an old Lee 10lb, but I recently acquired an old but little use Saeko (not sure if that is the correct spelling) that I used to do about 100 of the Lee bullets that I am using. Interestingly, the Saeko seems to come out of the spout so fast that I spent considerable time adjusting the little stop bolt so that it just "drizzled" out and I didn't make such a mess with overflow at the sprue. Sounds like I should keep it coming faster! I have dippers but have never tried pouring with them. Perhaps it is time to learn!

We are making a "town trip" (to Anchorage) in two weeks. I will attempt to find some tin.

Thank you for the details on modifying your mold. I am still of the opinion that my main problem is that the bullets are slightly undersized so I will likely go slowly down the path that you have illuminated. And yes, I do have a drill press. We have been here in the "bush" since 1977 and you are correct, one learns to be self-sufficient or heads back to town.

I shot another 25 rounds today with somewhat better results than last time. All were loaded with 13 grains Unique (which I believe will chrono about 1250, though my chrono is still ailing) except for 5 which I used 8.5 Unique to see if a lower speed would help stop the leading. It did not.

Nearly all groups ran just over 3". Not great, but as NuJudge pointed out, not all that bad considering. All but 5 were seated with the bullet base even with the cartridge neck rather than at the cannulure. Didn't solve the leading problem.

I cleaned the barrel after each five shots, always some lead but not extreme. One group I pushed a tight dry patch down the barrel after each shot. No difference in group size.

I had 5 cartridges left. 13.1 Unique, bullets hand lubed with RCBS and seated to the cannulure (heel of bullet about a quarter-inch below the neck of the cartridge.) I figured they would lead even worse than the others had. 5 shots, no cleaning between, group size 1 3/8"!! I pushed a tight dry patch down the bore and there were several streaks of lead on the patch. Go figure!

[Rickk]

[looseprojectile]

After you get your bore clean shine a bright light into the muzzel and look for copper. If you see any color at all it ain't clean enough. Drives me crazy.
I also use a bore mop with Thompsons bore butter or similar lube on barrels that try to lead. A very thin coat and maybe a dry patch after the grease mop will most always work for me. I am a firm believer of conditioning a bore for cast boolits.
My 375 rifle seems to want to lead worse than the pistol caliber leverguns, may be because of the longer boolit.
Anneal your case necks, trim the brass if needed, and you can use large pistol primers with your Unique loads. Keep after it. Waiting for your next reply.

Life is good

[TonyT]

I have used the old Lyman #378248 sized to 0.377" with SR-4756, SR-4759 and XMP-5744 in a pre-64 Winchester Model 70. I prefer the SR-4759 or XMP-5744.

[Rickk]

looseprojectile--AARGG! Yes, there are flecks of color in the grooves! I have the bore soaking in Wipeout now. I wonder if a few rounds of "firelapping" might help. I have done it on revolvers but never rifles.

How often do you mop the bore with the lube?

What does annealing the necks do? I am using new or once-fired starline brass. Neck-turned and trimmed. But not annealed.

Ha, I am down to only 300 large pistol primers so am using them sparingly. In fact tempted to experiment with large rifle in my 45 Colt and Casull! I see several posts in the past few days indicating the shortage may be letting up. Hope they get to Alaska soon!

TonyT -- Thank you. I assume you had success? My 375 is a post-64 model, but the one with cut checkering etc, not the really cheap looking ones. I am beginning to think, however, that the barrel is just a bit on the rough side.