would a 6mm international be good for cast

[WyomingWhitetail]

So ive been thinking about a new project again. Ive been thinking about a intermediate long range varmit and target gun in 6mm something. Thinking i would build off of a stevens 200 action and upgrade the gun as i shoot it. Then i got thinking about building it for cast so as i could shoot it a lot. I came across the old benchrest round of 6mm International and was wondering if anybody has info on how it would do with the RCBS boolit. The 6mm International is basically a necked down 250 savage (or necked up 22-250) with the shoulder bumped back. There are a ton of different variations but most have a pretty long neck and slightly less powder capacity than a .243 win. In my mind it seems like it should do well with cast but im a novice with these things. I fond a couple of thereads on hear that mention the 6 INT. but not a lot of info on it since its a pretty rare caliber anymore.

[Larry Gibson]

If it has the 12 or 14" twist for bench rest shooting it should be a good cast bullet cartridge. Just have to match a cast bullet design to the twist, neck length and the throat.

Larry Gibson

[runfiverun]

loads would be pretty simple to make/get/reference.
and like larry said a 12 twist would be very good.
if you picked a good boolit and had the rifle slightly short throated for it you would do rather well.
it would most likley get boring pretty quick.
i have a bbl and a couple of prototype cases kicking around for a long necked 300 savage.
it's finding someone to cut the chamber and a reamer that's the hold up.

[Doc Highwall]

Take a look at the 6mmXC.

[WyomingWhitetail]

Well from what I have found the RCBS mold is about the only one around in 6pm so that what would get used. Any thoughts on that mold.

[Larry Gibson]

I see Midway also lists the SAECO #243, an 85 gr TC. I kind of prefer the longer bearing surface of the RCBS mould though. There were 3 basic designs for the cartridge; the standard .250 case necked down, a Donaldson version with slightly shorter case and a 30 degree shoulder and the Walker version with the shoulder set back giving a longer neck. I believe the Walker version was the most popular. You might make a chamber cast to see which you have and also check the twist as a 14" twist may or may not stabilize the 95 gr RCBS cast bullet. I would also put out a WTB on a 245496 Lyman Lovern GC'd 84 gr mould.

Larry Gibson

[WyomingWhitetail]

Well just to make sure everything is clear. I do not own a rifle in this caliber at the present time. I don't even own i rifle to build one out of yet. My thinking was to buy one of the cheap Stevens 200 rifles in .243 or 22-250 and shoot it for a while and then over time i could put a better stock on it and a good trigger and then eventually re-barrel it as a dedicated cast shooter. I see i can get 1 in 14 shilen barrel pretty reasonable or a 1 in 12 i think. Seems like i would want the slowest twist i could get away with. I was thinking the walker version of the cartridge would be best because of the long neck. Im thinking his might make a dandy little varmint rig out to 500+ yards.

[Larry Gibson]

+1 on the 14" twist Shilen then and I'd keep it at 26" or longer. I'd also keep my eye out for the Lyman Lovern Mould. With the 14" twist and pushing to 2400+ fps that RCBS 95 gr bullet may stabilize. The Walker version would definately be my choice also. Sounds like a decent project in the making

Larry Gibson

[WyomingWhitetail]

Yea i was hoping with the slow twist barrel i would be able to push at least 2500 FPS with good accuracy at 400+ yards. Will it be easy probably not but would it be fun definitely. I was also planning on leaving the barrel very long (like 28 inches in a heavy varmint contour or even a full bull barrel contour). The goal behind this project would be to make a very economical, very accurate, very mild behaving long range varmint rig. Might eventually shoot a deer with it just for the heck of it but it wouldn't be the primary use. Now just gotta come up with the money to do it, which seems to always be a problem lol.

[runfiverun]

don't get the 22-250 then, you'll like it too much to change it.
another possibility is to look at some used target rifles with the clear intent to do the chambering and such.
just don't shoot it first.
i have three custom rifles and one in the halfway stage.
two were purpose built for hunting,one was bought to make into a bench cast rifle, then i shot it.
the bbl for that one is gonna get turned down and chambered for little girls hunting rifle.
strike two.
so after starting over again i now have a half built, needs a lot of stuff rifle,a 14 twist bbl blank,and a trigger.
all set to go [sigh] maybe.

[WyomingWhitetail]

Well the reason I was thinking of the 22-250 is that way I could shoot while I build up my parts and then after the conversion I could still use my brass. I was thinking .243 also since I really don't have a big desire to own a .243 I wouldn't feel bad rechambering. I don't think the factory barrel could be set back enough to re-chamber for the 6mm International or that would give me the chance to get it done right off the bat. The factory barrel would be fast a twist for cast but at least then I could play with the cartridge while I save for a barrel.

[Pat I.]

A few things learned through experience. First is that by the time you buy the rifle, buy a barrel, buy a good stock, buy a good trigger, buy a good scope so you can take advantage of it, get the barrel fitted, get the stock bedded, and the list goes on and on you're still stuck with a Savage 200 action that wouldn't bring squat if you ever decided to sell it. Second is that you're stuck with a small collection of bullet styles by choosing anything other than a 30 caliber. If you just have to have a 6mm use the proven one, the 6PPC. Otherwise if you're set on building a rifle go with the 30 BR. At the very least find an old Remington action for the simple reason that you can find all kinds of custom parts for it and smiths are used to working on it.

My first cast bullet BR rig was built on a Savage action and while they're good actions if you're planning to build an accurate rifle on a production action Remington is the only way to go.

Another choice and probably the best for what you're talking about would be to save up until you can buy a new or used Savage BVSS in .308 or 22/250. It has most of the stuff you need built in and there's companies that make drop in barrels in a slew of calibers.

[GabbyM]

Take a look at the 6mmXC.

2nd that.

David Tubb (davidtubb dot com) has standardized the 6mm-22-250 wildcats.
Norma makes 6XC brass for $69 per 100 or you can still form it from 22-250 cases.
Neck is .305” long compared to my 243 Win at .241”. 6XC case holds about 7 grains less powder than a 243 Win.

I was all worked up over the 6XC until I got my 243 AI up and running on cast and turned in a single digit E.S. five shot string over the chronograph. Typical E.S is in the teens. That using old Win brass fired several times in a standard 243 Win then annealed and fire formed in the Ackley chamber. So now I’ll just stick with the 243 AI since I’ve hundreds of dollars tied up in dies and a chamber reamer. Plus piles of brass.

Advantage of the 6XC over the 6mm BR is the XC will magazine feed. Case is straighter than its parent 22-250 as it’s been blown out to .455” from .414” at the shoulder.

I think the ideal dedicated 6mm cast shooter would be a 6mm-222. Mostly economics as I’ve enough 5.56 x 45mm here to fill a five gallon bucket and then there is the powder efficiency. However I seriously doubt the smaller case capacity alone would gain you much on accuracy.

[Larry Gibson]

I think for WyomingWhitetails application of HV for longer range varmint shooting a larger case capacity is best with a longer neck to support the cast bullets bearing srface and lube grooves. The 250 Savage case seems a good balance of case capacity to keeping the psi under 40,000 for the use of slow burning powders (RL19, AA4350, H4831SC and perhaps RL22) to achieve 2400 - 2500+ fps with 85 - 95 gr cast bullets.

The Walker design seems to fit the bill to me as it has the case capacity and the neck length. I have to agree with Pat that the .30 cal is a lot easier to get accuracy with and the choice of appropriate cartridges and barrel twists is there. However, as bullet weight goes so does recoil which is a consideration with a varmint rifle if one wants to spot his own hits/misses. It is easier to cast quality 6mm's than .225s, it's easier to cast quality .258s than either of those, etc. At some point, with a varmint rifle cartridge, you have to make trade offs and comprimises.

I know Shuz out my way (over in Spokane) is getting some remarkable results with a couple of 250 Savages. Some of us have had much better HV results with the 22-250 with 14" twist than with .223s with 12" twists. I know I get higher velocity with equal accuracy from my 14" twist 22-250 than I did with my 14" twist 222 Rem, the slower powder used in the larger case of the 22-250 is the apparent reason.

I just gotta think, if one wants a smaller caliber cast bullet cartridge, that the Walker version of the 6mm Int'l might be just such a dandy longer range cast bullet varmint cartridge with the right bullet/twist.

Larry Gibson

[WyomingWhitetail]

For some reason ive never been that into .30 cal. Ill agree that the .308, 30-06 and, 30-30 are three of the best rounds ever invented but the only one that really holds interest to me is the 30-30. Now you take a 30-06 and neck it up or down then im interested. The main reason that i want the 6mm is because its a good overall caliber size. Big enough to be legal on deer, small enough not to be overkill for varmints. Plus it gives just that little bit of extra energy at long range for varmints. As far as building on a Stevens action they are the exact same as the savage actions and savage has built a name around being accurate out of the box. Plus a lot of people make parts for the savage. Yea a Remington action would be nice (i actually have part of one but it needs a lot of parts) but im not going to pay 700 bucks for a rifle just to strip it (i am a college kid afterall). Plus i will be doing all the work myself so there will be no gunsmithing fees. I also don't build guns with plans of selling them, I build them because i like to create things and i like to build a little bit of myself into every project Ill let my unborn children worry about how much the action is worth once im dead.

[GabbyM]

Larry may have something there with a 250 Savage.
Just looked on there site and a new 250 comes with a 1-10” twist instead of the old 1-14” twist rate.
Savage used to do special orders for fifty dollars. They still have a special order phone number listed on there site.
Couple years ago I crunched the numbers on purchasing a Savage for the action then building a rifle. Not really a money saver there.