how muching sizing down????

[tmax64]

I saw a 312-185gr GC mold for sale cheap and was wondering how much you can size down a bullet. I would be casting for a 30-06 and possibly a 308. I haven't slugged the bore of either but am thinking that a 312 mold, even if it throws a little small would give me room to size down to fit. From all the reading I've done here it makes me wonder if the .309 molds are normally big enough. Lee sizers a pretty cheap to experiment with but is sizing down 0.002 to 0.004 too much? Thanks for your answers in advance. Tmax

[sisiphunter]

I've been told .002" is the max to size down, but I have sized a 312 to 309 for use in a 30-30 and had great results. I'd say do it, you want groove dia to .001 or .002 over groove sometimes too. Most of you lyman mold cast to .311 for a 30 cal, so whats .001 more really.....

That mold you found is likely the lee mold for use in 303 brit. I have one as well and am happy with it. Works in a good number of my rifles.

Good luck, Matt

[Smoke-um if you got-um]

Sizing down..... everybody has their own opinions and experiences with this topic. My own experience is sizing down 2 thou has no adverse effects. Your 30-06 should shoot fine with with a 310 or 311. You might even get by ok with the full 312. I usually try an as cast bullet in the case mouth of a fired case from the gun I will be using and see if it enters without much resistance. If it does I either leave it alone and seat the check at that size or perhaps 1 thou smaller. I then dip the bullets base down in an alox/mineral spirits mix and set them on a paper plate to dry. I dip twice before shooting. If the mold drops at 313 or 314 with your alloy it "might" be ok. Sizing down to no bigger than 312. After that it's up to the rifle if it will shoot acceptably. If the die is really cheap it would be worthwhile to get and test with. My own 30-06's do not like anything bigger than 311 but my 308 and 30-30's will shoot as cast 312's fine. Good luck.

Mike

[Hang Fire]

As a matter of course I size down (Lee push through die) .324" to .316' with no problems.

Here is more info from THE VERSATILITY OF LEE SIZING DIES" Paul W. Brasky, (Kingston, N.Y.) found in Castpics, The Versatility of Lee Sizing Dies, Articles By Members: http://www.castpics.net/

"From time to time, it becomes necessary or even desirable to radically resize a cast bullet to fit a particular rifle’s bore. By radically I mean as much as a .012” reduction. Why would you do such a thing? Curiosity is one reason, since we’ve all read that resizing by more than say .005” distorts the bullet and significantly reduces accuracy. Haven’t you wondered whether that bit of conventional wisdom is true? Another reason is that you may be searching for a bullet to fit a particular bore and what you want isn’t readily available, but you do have a likely candidate on hand even though it’s too wide. For example, I needed a bullet for my 7.65 x 53mm Argentine Mauser, which fitted it better than Lyman #314299. Having seen such a discussion on Shooters Talk > Cast Bullet site, and having corresponded with Rick Tunell, its principal advocate, about it, I was determined to see for myself whether it was true. I just happened to have a Lee .314” sizing die and a supply of LBT .326” cast bullets on hand as well.

Using my Lyman 450 lube-sizer, I lubed, applied gas checks, and sized to .326” 20 LBT bullets, making sure all lube grooves were completely filled (so as to support the driving bands when reformed). I next took a .314” Lee sizing die, screwed it into my press, smeared the .326” bullets with case lube (Use no more than you would when resizing brass.) and sized them down in one stroke to the smaller diameter. You’ll need a strong press, a stronger workbench and a bit of muscle for this, but little else except an open mind. When loaded over 22gr. of Accurate Arms’ XMP 5744, 20 rounds with the radically resized LBT (at .314” and seated to touch the rifling) shot identically to 20 rounds loaded with the same powder and charge, but Lyman #314299 (at .314” and seated to touch the rifling). Let me repeat there was no loss of accuracy with the reformed slugs. I’ve repeated this several times in the Argentine Mauser with bullets meant for the 8mm Mauser (Lyman #323471 and a Lee custom run of a 236gr. .326” bullet) but always with the same, satisfying results."

[peerlesscowboy]

In my experience sizing down .002" is about the limit, at least that's the case with a Lyman or RCBS sizer that pushes the bullet down base first. .004" & you're liable to bump the nose up so much that it won't fit in the chamber.

John C. Saubak

[Le Loup Solitaire]

There is a school of thought that says that shooting cast bullets as cast is the best way to go. Another theory is that sizing damages the bullets and the less that is done the better it is. Shooting bullets as cast is not always possible and some folks believe that a cast bullet should be .001-.002 over the groove diameter for several reasons. Whichever theory you choose to subscribe to, the guiding factor remains accuracy. Whatever tightens your group...do it. You may have to try each of the above approaches to find what works best for each of your guns. LLS

[nelsonted1]

I have a Brit enfield with a hugely oversized bore. I size .324 8mm bullets through a .316 sizer and have a great shooter.

There was a gun writer in the 1960s who chambered a .310 bore with a .45 acp chamber and it shot fine. The article is mentioned occasionally here but no one seems to have been able to find it, the actual article I mean.

[Mk42gunner]

I saw a 312-185gr GC mold for sale cheap and was wondering how much you can size down a bullet. I would be casting for a 30-06 and possibly a 308. I haven't slugged the bore of either but am thinking that a 312 mold, even if it throws a little small would give me room to size down to fit. From all the reading I've done here it makes me wonder if the .309 molds are normally big enough. Lee sizers a pretty cheap to experiment with but is sizing down 0.002 to 0.004 too much? Thanks for your answers in advance. Tmax

tmax64,

I have the Lee 312-185, it is my most used 30-31 caliber rifle mold. Mine drops aircooled wheelweights at .313" diameter. I lube and apply gaschecks in a .313" die with my RCBS lubamatic; this diameter fits most of my rifles, but a few need .311". Those I send through a Lee .311"die.

The best thing is to slug your bore before ordering your sizing die. Fit is important.

Robert

[tmax64]

Okay, I slugged the bore of my 30-06 with a 357 bullet I had laying around and I got right at 0.307 with my dial calipers. I think the bullet was a little hard to use as a slug but it seemed to work. Best I could do with what I got available. I'm thinking that I'll wait and get the RanchDog mold that is on backorder instead of getting "cheap". Thanks for all yall's help and input.

[singleshot]

I have the same question. I have a 35 rem (just aquired) in Marlin 336. I don't like the current lot of 35 cal designs so I've wondered if I could moosh (technical term) down a 366 or 375 bullet to size.

[geargnasher]

I have the same question. I have a 35 rem (just aquired) in Marlin 336. I don't like the current lot of 35 cal designs so I've wondered if I could moosh (technical term) down a 366 or 375 bullet to size.

Your best solution is to have Mountain Molds, Accurate Molds, or LBT make a mould you DO like. BRP or Ranch Dog might have a design on hand that will work very well in your gun. Go to LASC's website and read Glen Fryxell's articles on Marlin rifles and the .35 Remington (the "other" rifle he calls it), you will learn much. Ranch Dog (one of our banner sponsors) has been designing nothing but custom moulds for Marlin leverguns for years, he's what we'd call and expert in this arena.

Gear

[singleshot]

Your best solution is to have Mountain Molds, Accurate Molds, or LBT make a mould you DO like. BRP or Ranch Dog might have a design on hand that will work very well in your gun. Go to LASC's website and read Glen Fryxell's articles on Marlin rifles and the .35 Remington (the "other" rifle he calls it), you will learn much. Ranch Dog (one of our banner sponsors) has been designing nothing but custom moulds for Marlin leverguns for years, he's what we'd call and expert in this arena.

Gear

Yep, that's my next choice, Ranch Dog that is. I've gotta decide if I can live with a 190 grain 35 cal...a six hole mould makes for fast casting though.