Advice on finding correct mold.

  • 367 Views
  • Last Post 21 February 2020
Biddle1990 posted this 15 February 2020

Hello all.

Cast my first bullets recently for my martini Henry and it's becoming a slippery slope! It's rather satisfying!

Anyhow, now looking at getting another mold. This one will be for my .303s, 7.7 Japanese and 7.62x54r. now, there are plenty of molds out there for these. I want to find an ideal one for all of them. To do this, I have to slug all the bores. Now my plan for doing that presently is to do a chamber cast . This way I can reuse the alloy on each rifle instead of having to buy multiple slugs. Just thought I would ask the experts over here first!

Any and all advice is very welcome!

Attached Files

Order By: Standard | Newest | Votes
M3 Mitch posted this 15 February 2020

Well, I don't shoot any of these, but, most of them would be served at least OK by a heavy, gas check bullet a bit bigger than the usual .310-.311 diameter, not sure Lyman is still making it, but they have or had a bullet intended for the .303.  That said you need to measure the chamber throat, not the bore itself, in all 3 rifles.  Frankly I would be surprised if the 7.62x54 is not a good bit smaller diameter than the other 2, and while you can size down an oversized bullet I think you would be better served by at least 2, and possibly 3 molds, one for each rifle if they are different sizes.  If you want to use a traditional lube-sizer, you will need probably 2 and maybe 3 "H & I" dies as well. 

What are you wanting to accomplish?  You intend to shoot in military matches, hunt, just plink, or all 3?

Attached Files

Biddle1990 posted this 15 February 2020

Mainly just target shooting for fun. I get okay results with jacketed bullets. My no4 in particular has had a hard service life. Currently getting 5" groups while my others shoot well under that.

Attached Files

RicinYakima posted this 15 February 2020

What M3 said. When you know the diameter of the largest throat, get a custom NOE or Accurate mould heavy plus (200 grains) and what every sizers you need to make them fit. If you buy off the shelf these days, you will have to buy four or five for every rifle to finds something that fits. One right mould is less than five Lee's.

Attached Files

  • Liked by
  • Bud Hyett
  • M3 Mitch
Biddle1990 posted this 15 February 2020

Cheers. What some appropriatly sized fishing weights should be okay to slug all the rifles in question?

Attached Files

delmarskid posted this 15 February 2020

5/16" works out close to .312". 3/8" is .375" if you have small wrenches to fit and try weights you can probably find something that works. I have hit lead bullets with a hammer while they were standing on end to make them fatter. I bet that would work for you using fishing weights.

Attached Files

Brodie posted this 18 February 2020

What you really need to do is make a chamber cast or a "pound cast" on each of the rifles.  One of the greatest detriments to accuracy , especially in mil-surps, is the bullet entering the bore canted or less than straight.  This bends and mal-forms the bullet making it wobble off course upon exiting the barrel.  If you don' know how to make a pound cast just holler and we will be glad to help.

't

B.E.Brickey

Attached Files

pisco posted this 18 February 2020

when i bought my 310 a few years ago i got a lend of a mould and tried the cast bullet ,slugged the barrel,and done a chamber cast and sent it all to CBE and  dave sorted out what i needed

turned out the old mould was not cut like that any more and the new cutter was better for the heeled projectile 

 

Attached Files

Ed Harris posted this 18 February 2020

Best, cheapest solution is to do a pound cast of each rifle.  Then measure and have Tom at Accurate Molds cut a bullet to fit the largest rifle of the batch. His 31-215B (GC) or BB (beveled plain based) works in most.  Of the NOE designs #316299 works in most.  Get several Lee push-through sizers starting in .314."  For rifles in which you need larger send to DougGuy in NC to hone as needed to .315, .316 etc.

Be advised that with rifles having odd number of grooves you need to wrap bore slug with paper and measure over that and subtract twice the paper thickness.  I've found that a .316" sizer works for most of my .303s and Russian 7.62x54Rs, whereas a .314" stock Lee push-through works with US M1917, and US .30-40 Krags and much-worn '03 Springfields which have been shot a great deal with jacketed bullets and have worn throats.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

Attached Files

M3 Mitch posted this 19 February 2020

How much difference between the biggest and smallest throat would you guys say is OK to just use one mold sized for the biggest one, versus a difference that would make you think you need at least 2 molds to accommodate?  I guess for plinking that would be maybe about 3 or 4 thousandths, probably for match use less than that?  Anybody have practical experience?

Attached Files

45 2.1 posted this 19 February 2020

How much difference between the biggest and smallest throat would you guys say is OK to just use one mold sized for the biggest one, versus a difference that would make you think you need at least 2 molds to accommodate?  I guess for plinking that would be maybe about 3 or 4 thousandths, probably for match use less than that?  Anybody have practical experience?

I'll give you an example of what can happen with one bullet. Many years ago I had a series of stock Jap Type 99's, which is the 7.7 Jap cartridge. These rifles had groove diameters of 0.313", 0.314", 0.315" and 0.316" with tight throats which is a little unusual with these....... much the same as what you're asking about. I had a good load that shot well in most Jap rifles...... using the Lyman 314299 which cast at 0.315" after ageing. I sized for each rifle which basically was a bunch of bullets at one thousandth intervals and loaded the same load in each. The results did not go along with what you read is supposed to happen though. The 0.313" rifle shot really well and produced 1/2" groups, the 0.314" rifle produced 1" groups, the 0.315" rifle produced 2" groups and the 0.316" rifle produced 4" groups. The point here is fitting the throat is not necessarily what you want as the prime thing to fit a rifle. The nose diameter and shape has a lot more to do with accuracy the what you size the body to.

Attached Files

  • Liked by
  • M3 Mitch
John Alexander posted this 19 February 2020

45 2.1 sez:

"The point here is fitting the throat is not necessarily what you want as the prime thing to fit a rifle. The nose diameter and shape has a lot more to do with accuracy the what you size the body to."

This agrees with what I have found with long bore riding bullets similar to  the 299.

John

Attached Files

  • Liked by
  • M3 Mitch
Brodie posted this 20 February 2020

That is all wonderful, but what shapes seem to give the best accuracy?

 

B.E.Brickey

Attached Files

45 2.1 posted this 20 February 2020

It's the shape that actually touches the rifling in front of the case neck. It's different for different calibers and throating styles. I know, it still doesn't tell you anything...does it. Best that can be done when NOBODY puts any information in the question..................................................

Attached Files

45 2.1 posted this 21 February 2020

That is all wonderful, but what shapes seem to give the best accuracy?

Well, my previous answer didn't generate any information, so let's give an explanation and assume some things to help give a general answer. Let's assume we have a new to the shooter rifle. It's been used and hunted with by a normal once a year hunter and has about 200 rounds of factory jacketed thru it. The factories don't put the same throat in every rifle, it differs by manufacturer.... some have a small freebore and some have a steep taper into the rifling. that doesn't matter to much after the rifle has been shot with enough jacketed. The bore at the first tightest spot will erode and lengthen the throat with enough shots. The throat won't have one straight continuous taper, but will have two tapers which will erode at the first tightest spot there and will look like a curve which flattens toward the rifling. The throat lengthens slightly while this is going on. What fits this scenario which happens in a lot of rifles? Many attempts have been made to solve this. The whole trick ( if one can call it a trick) is to get the bullet in the rifling fully concentric with the rifling without damaging it. The answer usually is to introduce it into the throat with a long pressure curve and engrave the bullet gradually (not jam it in one instant into full engagement). In my experience, that works quite well. I know, gradually while involving milli-seconds is a misnomer, but that's how it is. The shape of the nose is generally two tapers, much like the Lyman 311672 (which BTW is a very good bullet in some rifles). Those angles are really finicky if you expect for accuracy to happen in the smaller MOA ranges, but it does happen when you get it right.

 

Attached Files

  • Liked by
  • RicinYakima
Close