Anyone with experience on sizing one caliber into another?

[00Scot]

I have another thread going where I asked for ideas on calibers that can be made from 308 brass. I have a large lot of 308 Lake City Brass. Form what I have read from a number of sources it seems that the LC brass is thicker then most 308 brass. I have not yet verified this but I will before I get deep into this project.

So here is what I would like to do. I want to use my large lot of matching Lake City 308 brass and turn it into a new caliber. Something in the 6-6.5mm range. On my other thread someone mentioned the 260 AI. From the first bit of info I read on this caliber I really like what I see. so.....here is my question. To get my 308 brass to the new 260 AI it looks like I am in for a number of steps. One article mentioned that he used the 260 rem as the parent case which is made from the 243 as the parent which in turn was made from the 308 as the parent case. At least that is my understanding of it. (I could be wrong on that and please correct me if I am) But assuming that is the progression of the cartridge will I need to swage (I hope that is the correct term) or form the 308 brass into the 243 first then the 260rem then the 260AI? Or can I go from the 308 straight to the 260 AI?

This will be my first caliber conversion on brass so any and all info will be greatly appreciated! Or if you can point me to a good read on the subject that would help a lot as well.

I know there are easier ways such as just buying 260 brass. But I don't want to take the easy way. I want to learn this process and to use this project as an educational tool and for the experience.

Right now I am in the research stage so I am in no rush and I know that I have a lot to learn before I attempt this. I have been out of shooting and reloading for over ten years. So I actually have a fair bit of reading just to get me back to my old knowledge base. Then I need to learn what I need to to attempt this project.

Thanks in advance for any help you can offer!

 

[alf]

243, 260, and 7-08 can all be made from your 308 brass, most times with only one pass through the full length die.

Thickening of the necks is really your only concern, depending on the neck diameter of the chamber.

If they're fired, I'd anneal them first. If you do an Ackley, neck them down till you get a snug fit when chambered, to get a proper fireformed case.

 

[bozo699]

00scot,
Welcome to the forum, I have followed your other thread and would agree with others, sell the brass and buy .260 Lapua but since you just want it for hunting and apparently want to fool around and experiment and just have some fun then go ahead and use the LC brass. Yes you can easily resize it to .260, I would do it an a couple or three increments but if you don't have the bushings or dies then buy a can of imperial sizing wax and a .260 die and size them, use the cow fire forming method and you will have your .260 AI cases and can go from there, hope this helps some, if you decide for sure let us know and we can walk you through step by step.
Wayne.

 

[00Scot]

243, 260, and 7-08 can all be made from your 308 brass, most times with only one pass through the full length die.

Thickening of the necks is really your only concern, depending on the neck diameter of the chamber.

If they're fired, I'd anneal them first. If you do an Ackley, neck them down till you get a snug fit when chambered, to get a proper fireformed case.

Thank you!

 

[00Scot]

00scot,
Welcome to the forum, I have followed your other thread and would agree with others, sell the brass and buy .260 Lapua but since you just want it for hunting and apparently want to fool around and experiment and just have some fun then go ahead and use the LC brass. Yes you can easily resize it to .260, I would do it an a couple or three increments but if you don't have the bushings or dies then buy a can of imperial sizing wax and a .260 die and size them, use the cow fire forming method and you will have your .260 AI cases and can go from there, hope this helps some, if you decide for sure let us know and we can walk you through step by step.
Wayne.

Thank you! And I do plan to buy whatever dies and tools I need to do this conversion correctly. I don't care how many steps it takes. I just want the best end product or outcome for this project. Plus the reloading work is half the fun anyway. (Time out in the shop and away from all the noise as well as a whole bunch of piece and quiet) I like the idea of multiple steps

I will deferentially keep you all informed and will absolutely be asking for more help along the way. But the deal isn't signed yet. I'm still looking at and for other ideas on the cartridge. But so far the 260AI is the front runner! It sounds like it will shoot better at 1000 yards then my 308 does and that is a plus. But not the goal of this project. But it is a plus for sure!

 

[4xforfun]

243, 260, and 7-08 can all be made from your 308 brass, most times with only one pass through the full length die.

Thickening of the necks is really your only concern, depending on the neck diameter of the chamber.

If they're fired, I'd anneal them first. If you do an Ackley, neck them down till you get a snug fit when chambered, to get a proper fireformed case.

To add to Alf's comments....You can make all of the claibers listed above....you CAN'T make an AI case without shooting them out of a gun...that is how all "improved" casses are formed.....insert a standard case in an AI chambered gun...pull the trigger and you now have a shiny new "improved" case.

 

[djtjr]

00scot,
Welcome to the forum, I have followed your other thread and would agree with others, sell the brass and buy .260 Lapua but since you just want it for hunting and apparently want to fool around and experiment and just have some fun then go ahead and use the LC brass. Yes you can easily resize it to .260, I would do it an a couple or three increments but if you don't have the bushings or dies then buy a can of imperial sizing wax and a .260 die and size them, use the cow fire forming method and you will have your .260 AI cases and can go from there, hope this helps some, if you decide for sure let us know and we can walk you through step by step.
Wayne.

Thank you! And I do plan to buy whatever dies and tools I need to do this conversion correctly. I don't care how many steps it takes. I just want the best end product or outcome for this project. Plus the reloading work is half the fun anyway. (Time out in the shop and away from all the noise as well as a whole bunch of piece and quiet) I like the idea of multiple steps

I will deferentially keep you all informed and will absolutely be asking for more help along the way. But the deal isn't signed yet. I'm still looking at and for other ideas on the cartridge. But so far the 260AI is the front runner! It sounds like it will shoot better at 1000 yards then my 308 does and that is a plus. But not the goal of this project. But it is a plus for sure!

you are saying two different things as i read your last statement if you want the best end product go with the lapua brass and fireform with COW or with bullets seated a bit long. if you want to learn the process and enjoy reloading that is a differnt story but i doubt there are are many here tha would say you will get a better product from used LC 308 than from new lapua 260. good luck either way let us know how you do.
d

 

[bozo699]

you are saying two different things as i read your last statement if you want the best end product go with the lapua brass and fireform with COW or with bullets seated a bit long. if you want to learn the process and enjoy reloading that is a differnt story but[color=black[color=red]] i doubt there are are many here tha would say you will get a better product from used LC 308 than from new lapua 260.[/color] [/color] good luck either way let us know how you do.
d
[/quote]
I don't know any that would make that statement, if they do well.......... ??
Wayne.

 

[00Scot]

00scot,
Welcome to the forum, I have followed your other thread and would agree with others, sell the brass and buy .260 Lapua but since you just want it for hunting and apparently want to fool around and experiment and just have some fun then go ahead and use the LC brass. Yes you can easily resize it to .260, I would do it an a couple or three increments but if you don't have the bushings or dies then buy a can of imperial sizing wax and a .260 die and size them, use the cow fire forming method and you will have your .260 AI cases and can go from there, hope this helps some, if you decide for sure let us know and we can walk you through step by step.
Wayne.

Thank you! And I do plan to buy whatever dies and tools I need to do this conversion correctly. I don't care how many steps it takes. I just want the best end product or outcome for this project. Plus the reloading work is half the fun anyway. (Time out in the shop and away from all the noise as well as a whole bunch of piece and quiet) I like the idea of multiple steps

I will deferentially keep you all informed and will absolutely be asking for more help along the way. But the deal isn't signed yet. I'm still looking at and for other ideas on the cartridge. But so far the 260AI is the front runner! It sounds like it will shoot better at 1000 yards then my 308 does and that is a plus. But not the goal of this project. But it is a plus for sure!

you are saying two different things as i read your last statement if you want the best end product go with the lapua brass and fireform with COW or with bullets seated a bit long. if you want to learn the process and enjoy reloading that is a differnt story but i doubt there are are many here tha would say you will get a better product from used LC 308 than from new lapua 260. good luck either way let us know how you do.
d

By best end product I meant best end product for my purposes. This will be a hunting rifle so I'm not looking for competition results. Just an accurate rifle I can take anything from Coyote to boar and deer with.

I want to see what "I" can do with this lot of brass. I understand that I can buy other or "better" brass. But I want to see how well I can get this LC brass to perform for me. With the thicker case walls I figured this brass would be a good contender for a conversion. I have never attempted one so I figured this brass would be a good batch to start it with. Plus if I have trouble with the process I wont be bothered if I loose a bunch of cases. I have more then I could ever need for this project so it is perfect for this situation.

If I was working up a comp load and rig I would buy other brass. But for this hunter this brass will make for the perfect platform for what I want and need out of the load and rig.

 

[2506]

If you use your 308 cases to make 260 Rem cases your neck length will be close to 10 thousands shorter than the trim to length. If you go to 260AI they will be even shorter. You WILL have to turn the case necks because they WILL be too thick. You WILL have to back off at least one full grain of powder when working up loads because LC brass IS THICKER and has less internal room. Another thing to take into account. Most LC 7.62X51 cases floating around were shot in a machine gun that has large chambers and the cases are really stretched and will not last long because the web area will crack or separate quickly. With all the work that it will take to get these cases to even be sub-standard that will fire in a 260 or 260AI. I would trade or sale them off and get Lupua cases if I wanted a 260 or 260AI or I would just keep the LC cases and get me a 308.

 

[Elkbane]

00Scott,
I've made regular 260 Rem brass from Lapua 308 before. Tried going striaght from 308 to 260 and also tried using a 7mm-08 die as an intermediate step. Using a 7mm-08 die first, then a 260 die made for straighter necks on the finished case tha trying to do it in one step. I don't have an AI so never had to deal with that. The only drawback of this conversion is that you'll end up with really short necks. The case OAl of 308 is 2.015" nominal and for 260 its 2.035". Average length on my 308 cases was 2.012" and after conversion they averaged 2.018". That may or may not bother you, but its pretty far off spec. I would think foreforming them to 260Ai would make them shorter still? Don't know for sure - I've never doen that.
Elkbane

Anyway, I'd do a test batch of 20 or so and see how it works before I got too much effort tied up in it.....

 

[00Scot]

If you use your 308 cases to make 260 Rem cases your neck length will be close to 10 thousands shorter than the trim to length. If you go to 260AI they will be even shorter. You WILL have to turn the case necks because they WILL be too thick. You WILL have to back off at least one full grain of powder when working up loads because LC brass IS THICKER and has less internal room. Another thing to take into account. Most LC 7.62X51 cases floating around were shot in a machine gun that has large chambers and the cases are really stretched and will not last long because the web area will crack or separate quickly. With all the work that it will take to get these cases to even be sub-standard that will fire in a 260 or 260AI. I would trade or sale them off and get Lupua cases if I wanted a 260 or 260AI or I would just keep the LC cases and get me a 308.

Thanks for the advice. I believe that I understand the amount of work it will take to get this done and I don't mind it at all. I enjoy the reloading process. To me it is another hobby just as much as the shooting and the hunting is. It is not just a means to an end for me.

I know the history of this brass and where it came form. It was ALL shot in High Power Competition Matches and in practice sessions by the same shooter from the same lot over a 2 year period.

I do already have a 308 that shoots real well. So I'm going to save some of this brass for when I shoot out the rest of my Lapua. Then I'll try to work up a new load with this brass. If I can't get it to shoot well with this brass then I can always go back to the Lapua.

Beyond that I will still have a huge amount of brass and want to do something that I have never done before with the rest of it. That is why I want to try the conversion. I want to learn how to do a conversion and with this lot I have a large supply of brass to attempt it with. So the only thing that I will loose form the experience is the time and effort. (other then the cost of the dies) But I will gain the experience and knowledge on how to do a conversion which is the single most important reason why I want to attempt it.

 

[00Scot]

00Scott,
I've made regular 260 Rem brass from Lapua 308 before. Tried going striaght from 308 to 260 and also tried using a 7mm-08 die as an intermediate step. Using a 7mm-08 die first, then a 260 die made for straighter necks on the finished case tha trying to do it in one step. I don't have an AI so never had to deal with that. The only drawback of this conversion is that you'll end up with really short necks. The case OAl of 308 is 2.015" nominal and for 260 its 2.035". Average length on my 308 cases was 2.012" and after conversion they averaged 2.018". That may or may not bother you, but its pretty far off spec. I would think foreforming them to 260Ai would make them shorter still? Don't know for sure - I've never doen that.
Elkbane

Anyway, I'd do a test batch of 20 or so and see how it works before I got too much effort tied up in it.....

Thanks Elkbane, I do plan to do a small test batch first just to see how it goes. If it doesn't turn out well then I will go another route. I'm just wondering how much the thicker LC brass is going to affect the conversion. I'm hoping that is is going to help the situation and not make it worse. We shall see....

 

[expiper]

dont forget...you will have to swage/ream the primer pockets on the LC mil. surpluss brass...!!!!,,,,,Roger

 

[00Scot]

dont forget...you will have to swage/ream the primer pockets on the LC mil. surpluss brass...!!!!,,,,,Roger

I'm certainly not looking forward to that part but it is what it is. It's gotta get done.

I never really thought about the age of this brass. It's from the 60's. How is that going to play a role in this project? Or will it?

 

[2644ever]

OOScot, unless you have a huge supply of that LC brass (I mean HUGE, by the thousands...) and have a personal reason to use it, I would just trade it and purchase the very best brass in as close a caliber as the one you intend to use. Years ago, I just did what you're planning to do. I had to load about 600 .260 cartridges for a very thorough testing session with a brand new precision rifle at several distances ranging from 400 yds up to 1200 yds. I was supplied with the requested amount of powder, primers and bullets, but my buddy couldn't retrieve 600 empty cases (fired or new) in any of the calibers you mentioned. Time was running short, so he brought about 600 once fired .308 military cases, Lapua made, all from the same crate and the same lot... They had been fired by a marksmanship unit in a dozen AI-AW's and were in good condition. As you might have guessed, the primer pockets needed to be reamed and the brass not being intended for reloading ( the original ammo is the HPS loaded with 170 grs fmj-bt Lock Base bullets), I knew the necks were somehow brittle as they're not annealed as carefully by Lapua. To make a long story short and because my buddy could't help me, between annealing , reaming, full length sizing in 2 steps (.308 without the expander ball and .260) measuring (thank you so much, Lee for your awesome Perfect Powder Measure) and precision seating of the bullets, it took me 10 friggin' days to complete the mission... Despite annealing, about 5% of the necks were lost on firing the rounds, requiring to disregard the culprits on the targets and shoot extra rounds in order to get meaningful results..
Would I go through all this again? Hell, no! Just think about it.

 

[00Scot]

OOScot, unless you have a huge supply of that LC brass (I mean HUGE, by the thousands...) and have a personal reason to use it, I would just trade it and purchase the very best brass in as close a caliber as the one you intend to use. Years ago, I just did what you're planning to do. I had to load about 600 .260 cartridges for a very thorough testing session with a brand new precision rifle at several distances ranging from 400 yds up to 1200 yds. I was supplied with the requested amount of powder, primers and bullets, but my buddy couldn't retrieve 600 empty cases (fired or new) in any of the calibers you mentioned. Time was running short, so he brought about 600 once fired .308 military cases, Lapua made, all from the same crate and the same lot... They had been fired by a marksmanship unit in a dozen AI-AW's and were in good condition. As you might have guessed, the primer pockets needed to be reamed and the brass not being intended for reloading ( the original ammo is the HPS loaded with 170 grs fmj-bt Lock Base bullets), I knew the necks were somehow brittle as they're not annealed as carefully by Lapua. To make a long story short and because my buddy could't help me, between annealing , reaming, full length sizing in 2 steps (.308 without the expander ball and .260) measuring (thank you so much, Lee for your awesome Perfect Powder Measure) and precision seating of the bullets, it took me 10 friggin' days to complete the mission... Despite annealing, about 5% of the necks were lost on firing the rounds, requiring to disregard the culprits on the targets and shoot extra rounds in order to get meaningful results..
Would I go through all this again? Hell, no! Just think about it.

Thank you 2664ever,

I don't mind the work and the time involved. Nor do I care how many days it will take to get there. I have no idea how many cases are in the 5gal bucket but I would guess at least 1k. Probably more. So I can loose some cases in the process.

I'm not looking for the best way to work up a load for the 260AI. Nor am I looking for the easiest way. I'm looking for the journey. I want to learn the process of caliber conversion and I have plenty of brass to use to do it. Time is not an issue, I have no restraints on time. So I can take as long as I need to to get this done.

I expect it to be frustrating and a pain in the arse at times. And I'm prepared for that.

If all I wanted was the end result of having a 260AI to shoot then I would just go buy one along with the brass and the dies. But that is not what I'm looking for with this project. I'm looking to learn how to do this. That's all.

I appreciate you sharing your experience and offering your advice.

 

[2644ever]

Well, I kinda like your attitude. If you have an initiatic journey in mind, I guarantee you'll get plenty of experience. Consider it as a crash course and enjoy every hour of it! Have Imperial Sizing Wax ready, it will come handy and it is easily removed if you dunk the cases (1 or 2 hundred at a tme) in a gallon of gasoline. 1 gallon is enough to degrease your 1,000 cases. Just let the brass dry in the open. Beats wiping every goddamn case with toilet paper...

 

[ShaneG.]

I recently built a 260ai with a CBI 28" 8twist barrel. First thing I did was order Redding 260ai dies and a Redding 260 Form die.

I also bought 100 7-08 cases and ran them through the form die,they go through it quite easy. Then lubed them up and ran them through my 260ai die. Since the AI chamber should be .004" shorter on headspace than a 260 remington you should have a slight crush fit,I also seated the bullets long to be into the rifling. I used a max load of powder listed for the standard 260rem. In my case I bought 100 cheap Prvi 120g hpbt and ran Alliant mr2000 powder. It will blow the shoulder out nice and sharp.

One thing I noticed is my loaded neck dia. was .288 with the necked down 7mm-08 brass. My chamber neck size measures .297" as close as i could measure. So I had a bunch of 308 brass I had necked down and loaded and it was measuring .294" a lot tighter but enough clearance I think to be good. I played with turning the necks on some of them as well to even them up.

I have used H4831,H4350,MR2000 and recently tried some Ramshot Magnum which I could not find data for. After working up a few loads for it to test velocity it got a 140hpbt over 3000fps. I'm gonna back off and try to run between 2900-2950 if it will shoot good there.

I would do like has been stated before and anneal your brass before necking down and sizing,I didn't have any split during forming but did split a few on firing and it was almost always the brass that gave me the largest neck to chamber clearance.

So far I like the 260ai,only shot it out to 630yards so far,next weekend going to shoot it at 1000 and see how it does. You'll definatley learn a few things and have some fun to boot. I would use some of the LC brass to get familiar with it then spring for some good stuff when you feel you can. Just make sure to measure neck clearance on the necked down 308 brass.

 

[00Scot]

Well, I kinda like your attitude. If you have an initiatic journey in mind, I guarantee you'll get plenty of experience. Consider it as a crash course and enjoy every hour of it! Have Imperial Sizing Wax ready, it will come handy and it is easily removed if you dunk the cases (1 or 2 hundred at a tme) in a gallon of gasoline. 1 gallon is enough to degrease your 1,000 cases. Just let the brass dry in the open. Beats wiping every goddamn case with toilet paper...

Got the wax and the gas. As for the paper.....hell no. I like the way you think.

Thank you for the info and encouragement!