6BR for Cast Bullet Benchrest

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djohns posted this 15 January 2008

I have a remington 700 that was built to shoot 1000 yard matches. It has a 30 inch douglas barrel 1-8 twist. It was built to shoot the 107 sierra matchking bullets. Would this be a good rifle to try cast bullets in. RCBS makes a 95 grain bullet in 6mm. The chamber in this rifle is throated long for the long sierra 107's. Would like someone else's thoughts on this and recommendations. I was going to rebarrel this rifle to 30br but since it is already 6br with a long throat, thought I might get it a try??

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CB posted this 15 January 2008

You could certainly try it. There only a couple of competitors shooting a 6mm now, both with twsit around 1-9” and 10".  What cartridge chamber do you have in that long range rifle? More than likely you wouldn't need the 30” barrel. As far as rifle equipment components, what works for the jacketed BR shooters at 100 & 200yds will work for CBs, 24"-27” barrels. Also as per jacketed BR, throat fit is critical to BR accuracy.

I have the RCBS mould and find the nose is too small. It just falls down the muzzle of my 6PPC, 243, barrels. That will shoot, but not be match accuracy. I need to lap out the nose section of the mould but haven't done it yet. CBE moulds makes a 100gr gas check bullet I thought about buying, thinking it might be big enough on the nose?..................Dan

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Tom Acheson posted this 15 January 2008

Dan,

Have you tried the Saeco 85-grain mould? I know it's not a long bullet for this particular chambering but wondered what your experiences with it were.

Thanks!

Tom

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djohns posted this 15 January 2008

Thanks for the heads up on the mould. I tried to order one from Buffalo arms and they were out of them. I called my friend Clyde and he said he has an old lyman that cast a 100 grain kind of sharp nose bullet, so I think I will give it a try first. This rifle has a long throat to it. You have just enough room to seat the 107 sierras out to the lands with the bullet seated almost to the bottom of the neck. I'm hoping this lead bullet will be long enough to reach the lands and still be down in the neck at least halfway, will just have to see. I do not have the reamer that cut the chamber in this rifle I borrowed one from a fellow that shot the 1000 yard matches and he would not sell it to me. I have a 6br reamer with a shorter throat and I might have to cut this chamber off rethread and rechamber with it. If I have to go to all that trouble I will probably just go ahead with the 30br, the 6br 1000 yard chamber shoots great and I would kind of like to save the barrel incase I get the fever to shot 1000 yards again,

Thanks for all the info I really appreciate it..djohns

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djohns posted this 15 January 2008

Dan I have never shot a lead bullet in a 6mm that I can recall. I called a friend of mine that has a zillon moulds and he happened to have an old Lyman 100 grain mould in 6mm. I am going to give it a try.

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Fred Sinclair posted this 15 January 2008

Please keep us posted on your project. I too have a 6BR w/ 8” twist and .100 long throat. I kinda' let the idea drop because of the lack of gas checks. Fred

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djohns posted this 15 January 2008

Will do Fred, and by the way are you the Fred Sinclair of benchrest fame. I started shooting benchrest with a sleeved remington 40x 6ppc 20 years ago. The rifle I was told when I bought it was built by Fred Sinclair.

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CB posted this 15 January 2008

The 6mmBR cartridge will be a little over-capacity for the bore. If you build a 6mm, I'd use the 6PPC cartridge. You can still get 6mm gas checks over on the Castboolits forum in group buys from Gatorchecks. Maybe Fred could put in a good word and make a deal with Gatorchecks to stock them at Sinclair International?  :)  That'd be great!

I think I know what Lyman mould you're talking about. It is a Loverin type design. I'd start out slow with something like AA5744 maybe 12-14gr at 1,600fps and see how it does. Then start cranking it up close to 2,000fps. I think a good powder choice may end up good with 4198 or VV N130?

Ya, I still have a PO Ackley barreled rifle and also nice Winchester with a Fred Sinclair barrel on it. Great prairie dog rifle in a 6mm-250!. Made a 520yd shot with it last spring..........Dan

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djohns posted this 16 January 2008

Thanks for the info Dan, I will try those loads and powders. I have a new 2lb container of N130 that I bought at a gunshow, I thought I was buying n133 and didn't notice I had the wrong powder until I got home.

I picked up the mould last night and it is a Lyman 245498, looks like it might be a good bullet to start with. He also had a new box of lyman 6mm gas checks, I was having trouble finding some.

I noticed in the tech data a lot of shooters are using 1 part lino to 1 part wheel weights. Is this the best way to go. I have plenty of lino and wheel weights. I also have lots of soft lead and a pretty good supply of tin but would like to save the soft lead and tin for my BPCR loads.

Also I have found that straight wall cases with cast lead bullets get better accuracy when I make an expander that is about .0005 under bullet diameter so that the bullets are not so hard to seat, will this work for these bottle neck cases also or do you recommend more neck tension.

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CB posted this 16 January 2008

DJ We generally run about .002 neck tension. Also I would plan on using an alloy that is in the 22 -26 bhn range. You will need the bullet strength to drive it 2000 fps or better. A general rule of thumb for cast bullets is the slower the twist, the shorter the bullet. it isnt as much the weight, but the length and bearing surface of the bullet for a given velocity that makes the difference.

Finding the velocity for a given length bullet will take experimentation, loading at the range will help you do that faster.

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djohns posted this 16 January 2008

Thanks jeff I will try your suggestions, you folks are sure a big help I really appreciate it.

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Fred Sinclair posted this 16 January 2008

Yep, tis me. About 6 years ago I built my rifle thinking I was going 1000 yard BR shooting. When I found out, that at some matches only the relay winners advance I had a change of heart. I'm sure as H---  not driving 250 plus miles only to shoot 5 or 10 rounds. That just wasn't gonna' work. The darn thing has less than 100 rounds thru it and is just sitting in the safe. I'm hoping you can figure out how to make your rifle work with cast so I can pick your brain. Fred 

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djohns posted this 16 January 2008

Fred

Will be glad to keep you posted. We have a real nice 1000 yard range down here at the AEDC military base. It is approx 50 miles from my house. I shot in about 10 different matches in the past 3 years. I started with the 6br cause I always was partial to it and a lot of the guys were have good suscess with it. I finally shot a 200 13X score with it. If it is real windy the 6.5 284 guys will kick your butt. I kind of lost interest after the 200 score but now they have made the 10 ring smaller and it is even harder to get a 200 score.

These matches are real informal down here and we usually shoot two 20 round matches and sometimes 3 20 round matches. I guess this is to far for you to drive but if you are ever interested just let me know. I would attend another match if you were there, it would be a pleasure to meet you.

 

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CB posted this 17 January 2008

dj,

You're a blessed man. Your friend's 245498 design is the best 6mm mould of the Lyman moulds. The Loverins are good for position match accuracy, but hardly ever seem to make it into the BR accuracy range. It is a bore-ride bullet, so after you cast some, push the nose of the cb into the muzzle of your rifle. It shouldn't fall in, but have just a little friction. Then try pushing it firmly into the throat with a bronze rod, knock it out and it should have land marks engrave on the nose. I inspect closely under a lighted magnifier, as fit is critical.

I assume you have a tight-neck chamber. The tight neck custom BR shooters like the 30BR don't size the neck usually, they load the bullet by hand just to the gas check. When closing the bolt, the bullet will bottom out in the throat and push back into the neck. If you have to resize though, Jeff is right about .002".

Don't alloy if you don't have to. That's just another factor to mess you up. If you have plenty of lino, just cast it. Lino cast great and can hardly be beat for ease of casting and shooting up to 2,200fps with synthetic lube. The guys using 50/50 Lino/WW are probably stretching their supply out and only shooting up to 1,800fps..............Dan

 

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djohns posted this 17 January 2008

Dan

I'm even more blessed to have met someone as helpful as you are on this forum. I have never got into forums before but sure glad I did this one.

 I have been full length resizing with a redding bushing die. The necks are turned but I'm only sizing a couple of thousands for the bullet to reseat. I have more brass and can neck some more so that I don't have to resize at all. I talked to the guy at LBT today Veral Smith and I'm gonna go ahead and order a 30 cal mould while he is still making them.

 He mentioned something about making a bump die to bump the bullets for a better fit in the throat. Is this what you are talking about when you say fit is critical. Is this die doing the same thing with each bullet as you describe with the brass rod, but you do it to all the bullets so they match the throat.

  He said you make the die with the same reamer you cut the chamber with. I don't have the reamer that cut the chamber in the 6br but I quess I could borrow it again if the guy still has it. Any light you could shed on this would be greatly appreciated. I'm always interested in new gadgets to make and experiment with.

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CB posted this 18 January 2008

If you are sizing your necks now, the cases will probably be alright for CBs. I was going to say remember you'll probably want to try sizing and lubing the CBa at .244", so you'll need to go up .001” or 2 in your bushing. The base of the bullet should be sized to the diameter in your long throat. Too big and it won't chamber, too small and it won't seal and lead the barrel.

The idea of bumping is to press the CB to the exact size of the throat. That is why you use the same chamber or throat reamer to make the die. Bumping usually involves 'bumping up' small parts of the bullet to the diameter of the reamer used. I do not use a bump die.

Your 107gr throat ought to take the LBT just fine. Be sure to size the base to the diameter of your throat. Seat the CB as far into the throat as possible. I suggested moderate loads to start because the pressures are forgiving to any ill-fitting of the CB. If you are not getting any leading problems and find decent accuracy, then load on up to 1,800-1,900fps with N130-N135 or 4895. Good luck and have fun!  :)................Dan

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djohns posted this 18 January 2008

Dan

Thanks again, I really appreciate all of this help. I read some of the other threads in the forum about this bumping thing and what you just told me confirms that my understanding is much better. You have been a great help.

There is a guy selling linotype on ebay and is listing it at 40.00 dollars for 40 lbs with flat rate shipping of 8.95. I have bought a couple of hundred more lbs from him in the last couple days. If anyone is interested I think he has some more listed. Just go to ebay and do a search for linotype and about 55 items will show up he is down at the bottom.

I hope to get a few bullets cast this weekend and see how they fit, but it is too cold here to shoot. Suspose to get down into the teens this weedend. I have range duty on saturday but will probably stay by the heater most of the time.

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CB posted this 18 January 2008

What do you mean too cold, we're having a registered match tomorrow at Wind Hill. Suppose to be down to -6F tonight with a high of 5F tomorrow and a wind chill of -11F!

Now days $1/lb ain't a bad price for Linotype. It's alway going to go up, for sure. Back in 1984-85 the Wind Hill bunch bought out a print shop at $.30/lb. I got 1,000lbs and sold have to a buddy. Altogether I think we got just over 12,000lbs out of there. Sure'd like to finda haul like that again!

This is good weather to stay inside and cast up next season's CBs. I cast Lino as hot as my electric pot will go, about 780F. I use a ladle cause it fills out the mould better, as those CBs are a little heavier than bottom poured CBs. Then get them to fit good in the throat, like a Chinese finger cuff. Full support from the nose to the opening of the throat. Most match shooters seat somewhere around or just at the gas check...............Dan

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djohns posted this 18 January 2008

Dan

Your last response reminded me of a joke. An old man was walking down the road and a frog jumped up beside him and said “kiss me and I will turn into a beautiful princess” The old man picked up the frog and put it in his pocket. The frog crawled up out of his pocket and said “hey old man did you not hear me, kiss me and I will turn into a beautiful princess” The old man pushed the frog back down into his pocket and said at my age I'd rather have a talking frog.

At my age I'd rather have a nice cozy warm place..Get it;)

There was a time though if it were below zero, snowing, sleeting, I'd be shooting or up in a tree waiting on a whitetail.:fire

 

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djohns posted this 20 January 2008

Dan

I cast some bullets with the lyman mould using linotype lead and the nose section is only .233 I need about .237 for them to ride the bore with a good snug fit. Can a swage or bump die be made to bump these up. I slugged the freebore section of the chamber and it measures .2435  The freebore section measures about .100 long and tapers into the rifling.

What would be better, it seems to me, is to have the nose section not a bore rider but large enough to fit this freebore and the nose to match the throat section. Is it possible to upset these linotype bullets that much with a swage die. I have a large corbin sytly press that I made a few years ago when I was experimenting with swaging 40 cal bullets for the 40-65, and it would not take too much work to make such a die. 

If you know for sure that this won't work let me know and I will cast some round slugs from the linotype and turn some test bullets on the cnc lathe to match the chamber and send one to a mold maker and have a mould made to match it.

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DonH posted this 21 January 2008

Unless one can make all these “bump dies", etc. himself it seems to me it would be more advantageous to have a mould cut to give the bullet fit you need right from the mould. If a mould has to accommodate more than one rifle, nothing beats a mould throwing a bullet of correct fit. The $120 or so (from B&D) for a custom mould is not so much compared to buying/trying sevaral moulds looking for something that works. For what it is worth, I am not flush with money and thought I could do it for less than the cost of a custom only to find that I would have been better off to have heeded advise of others.

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