Any advice on sizing .308 Winchester brass to be used in a 7mm-08 rifle?

[MCMXI]

I have quite a bit of .308 Winchester brass and I plan on keeping all of the Lapua stuff for my .308 match rifle. However, I'd like to resize a bunch of the other cases for a 7mm-08 Savage that I've 99% decided that I'm going to buy. I don't see any special sizing dies on Midway to "convert" cases from .308 Win to 7mm-08 so is it as easy as running the .308 Win cases through a 7mm-08 FL die? I've done some research but haven't found much useful information on the subject.

Any other advice, suggestions, wisdom to share?

Thanks.

 

[~z]

Thats how I used to do it with no problem at all. Trim to a uniform length after resizing and you are ready to go. Just make sure to keep em segregated from the regular .308s. I used to just use one headstamp. Now I have plenty of 7-08 brass (that actually says 7-08 on it) so I quit the resizing practice and gave away the resized brass.
~z

 

[MCMXI]

~z, this 7mm-08 deal is directly related to the pig hunt in August. Through no fault of my own (my wife's actually), I need to put together another rifle to take in addition to the .300 WSM so it'll be interesting to see how they compare. I'm planning on using the 139gr SST from Hornady.

So do you see any advantage to buying 7mm-08 brass (other than the headstamp) as compared to resizing .308 Win brass? I could easily resize all of the .308 Win brass that doesn't have LAPUA stamped on it ... that way I wouldn't mix them up.

 

[~z]

I didnt want to turn this into a Win Fed Rem brass discussion but I dont think you could go wrong with resizing the WIN brass. I just came into a good deal with the 7-08 brass and bought it. I never had a problem with the 308/708 stuff. All my 25-06 brass says 270 on it.

Oh, and good choice on the bullet. The pic in your sheep thread was taken with my 7-08 with the same bullet. I have found it to be very good to 400yds, (just a self imposed limit based on the optics I'm sure it will run farther)
What powder?
~z

 

[Ranb]

There are no forming dies for 308 to 7mm-08, just full length resize in the 7mm-08 die. But it might not work.

I have been shooting 308 for years, so I had lots of brass. After buying a savage 7mm-08, I thought it would be a simple matter to just neck it down and trim, but not so. The neck walls got a few thousands thicker and this was enough to make chambering difficult. I bought some new 7mm-08 instead. Some rifles may have a chamber wide enough, but mine did not.

Ranb

 

[~z]

Neck turning will remedy that but if the choice is neck sizing or buying 7-08 brass, I'd buy the 7-08 brass too.
~z

 

[MCMXI]

Well, the Savage has been ordered so now it's no longer an academic discussion.

~z, I'll be using either IMR 4895 or Varget and that's good news re the 139gr SST ... your sheep looks plenty dead. I've got about 200 FC cases and 100 WCC cases that I can start with.

There are no forming dies for 308 to 7mm-08, just full length resize in the 7mm-08 die. But it might not work.

I have been shooting 308 for years, so I had lots of brass. After buying a savage 7mm-08, I thought it would be a simple matter to just neck it down and trim, but not so. The neck walls got a few thousands thicker and this was enough to make chambering difficult. I bought some new 7mm-08 instead. Some rifles may have a chamber wide enough, but mine did not.

Thanks for the heads up. I've never owned a Savage before so I've got no idea about their chamber tolerances, throat length etc but I'll definitely keep an eye out for any problems.

 

[45ACPUSER]

You are probably going to have to neck turn and probably ream the case neck. A better idea is to NECK UP to make the the brass from say 260 or 243?. But, then in the end why not just buy the 7mm08 brass to begin with?

 

[MCMXI]

You are probably going to have to neck turn and probably ream the case neck. A better idea is to NECK UP to make the the brass from say 260 or 243?. But, then in the end why not just buy the 7mm08 brass to begin with?

Hence the post. Since I have no experience with this, feedback from good folks like yourself will help me make the right decision. Since I have a bunch of .308 cases that I'm not using in my .308, my first thought was to size them for the 7mm-08 since I don't like to waste perfectly good cases. However, as you and Ranb (and ~z) mentioned, it may be more trouble than it's worth. Perhaps a good approach may be to buy a box of 50/100 7mm-08 cases to start with so that I can begin load development. Since I'll have the dies, I could also try to form a few .308 Win cases from each manufacturer to see how they work out. I'll have "genuine" 7mm-08 cases for comparison both in terms of physical dimensions and how they feed/function in the Savage.

 

[ants]

Everything to gain, nothing to lose.

I'll report no problems in a Rem 700 chamber. Not only the 308-to-7 but also necking .30-06 down to 270. Thickness of the brass at the neck was completely within max spec. In fact, you can shoot and trim them a LOT before the neck gets fatigued.

Since you're ordering the rifle and have the 308 brass, might as well give it a try.
Got everything to gain and nothing to lose.

Just use standard 7-08 dies and lube the neck/shoulder (even though you would not normally lube the neck & shoulder, do it anyway). Use Lee case sizing lube or Imperial sizing wax. Other case lubes aren't slick enough sometimes. Let these sizing waxes dry and you won't dimple the cases.

• I use a Wen electric engraving scriber to put an X on the original 'parent' headstamp. Write a 7 in an empty spot on the head and no one will make a mistake.

 

[MCMXI]

I use a Wen electric engraving scriber to put an X on the original 'parent' headstamp. Write a 7 in an empty spot on the head and no one will make a mistake.

We have a really nice Telesis pin stamper at work so I could stamp 7mm-08 if need be and put a line through .308 Win ... in a nice arc around the case head too.

I'll report no problems in a Rem 700 chamber ... Got everything to gain and nothing to lose.

All of my bolt action rifles are 700s so this Savage will be a first for me and you're absolutely right about that. It'll be fun to form a few cases since I'll have the dies anyway. If it doesn't work out I'll save the .308 cases for the M1A (if it ever arrives).

Thanks to all for your help ... it's much appreciated.

 

[243winxb]

The outside neck diameter of a loaded round should never be larger than .315" when sizing down 308 brass for the 7mm-08. A donut may form at the neck shoulder junction. This can cause hard chambering if not removed. As said, just buy new 7mm-08 brass.

 

[freakshow10mm]

I've done it before when I had a 7mm-08 Tikka (the M595 I cry about having to sell). I used Redding FL bushing die. Bought the final neck size bushing plus one that split the difference. Less working of the brass and kept the necks straight. I had a consistent TIR of less than .003".

 

[interlock]

sizing .308 win to 7mm08

i have sized all but 50 of my rounds cases in this way. I just lubed them up and ran them trough my full length resizing die. the federal ones are fine, some of the ninchesters get a bit of a bump on the shoulder so might need to go through twice..

they are a milimeter or so shorter than 308 win so no need to length check- but make sure you have plenty of shank in the neck.

I have fancied those hornady bullets, they look good - but i wonder if they might be a bit quick expanding on big deep hogs with your pretty quick 7mm08 velocities? maybe the interlock might be a good choice? or speers 145 gr spitzer (a truly great game killer).

I have also sized up from .243. That works well aswell. when coming down from 308 plenty of lube (but not excessive its a balance)

interlock

 

[ranger335v]

"I don't see any special sizing dies on Midway to "convert" cases from .308 Win to 7mm-08 so is it as easy as running the .308 Win cases through a 7mm-08 FL die? "

Yep. Not only is it easy, it's safe too. I've made a lot of .243 that way, in a single step. I loose a few cases going that far in one step but going from .308 to 7mm (.284) will be a breeze.

The necks will thicken about 8% (The ratio between .308 and .284). Most necks are about .013", so add 8% = .014". A 284 bullet + (.014x2) = .312" approximate loaded diameter. That's easily 3 thou under max SAAMI neck for a 7-08. Most - likely all - factory chamber necks are somewhat larger than SAAMI minumum so it's unlikely you will need to thin the reformed necks. But, check the loaded diameter to be sure.

Gettng a neck "donut" in a reformed case comes from necking up, not down. Necking up draws some of the original shoulder into the new neck, necking down puts some of the original neck into the new shoulder.

Thus, I seriously doubt you will need do anything but check case length and it's not likely the reformed cases will be too long either.

You may want to consider annealing to prevent premature neck splits. ?? Maybe?

 

[GooseGestapo]

I've reformed quite a few cases for the 7mm08 from .308 as well as from .243.

The only time I've had neck diameter issues was with some PMC factory ammo I obtained with the new rifle.

The PMC factory ammo gave excessive pressure cases upon firing (burnished case heads and cratered primers.) Reloading yeilded cases that chaambered with considerable difficulty if at all. Having fired many different rifles/cartridges/calibers for several decades, this was the first time I'd encountered excessively thick necks.

I neck turned all the PMC brass, and it's now the best/most accurate brass I have for my rifle. All other cases of .308 that I've reformed have been thin enough not to require neck turning. In fact, the second best brass I've found for accuracy has been some Remington .243 brass that were range pickups that I reamed the flasholes, and neck turned for uniformity, and weight sorted before starting with them.

So, you rifle may not require any further attention than brand and weight sorting and simply running them through the 7mm08 sizer. However, if you've got a match chamber, or just a tight standard chamber as I do, then you may need to neck ream.

However, if the brass has been previously reloaded, you may need to trim too. Either way, I always trim to a uniform minimum OAL to start with, regardless of caliber/chambering.

Also, if you're using .308 that have previously reloaded, you may see some loss due to split necks and/or collapsed shoulder, especially if you use too much lube.

I suggest starting with once fired brass. I frequent a public range, and I've got hundreds of '06, '08, and various -magnum cases to play with. Heck, I don't even own a piece of "factory" brass for either my .257WbyMag. or the .338/06............. My .257cases are all .050" short because they're from 7mmRemMag cases. Dosen't hurt accuracy one iota.......

 

[counterclockwise]

Just finished developing my technique...

1.
I use an RCBS full length resizing die for 7mm-08.
Neck reducing loads are high and good lubrication is essential. Failure will result in a stuck case. I prefer RCBS-2 over Imperial. But, the RCBS-2 has to be replenished more often. Remove the expander stem. Step down the die about 2 turns at a time per stroke after the neck begins reducing.

2. About half way through the neck forming, stop and wipe of all the lube with paper towel. Trim the half finished case to a preset 2.025. [Not only is the neck getting thicker, but it is getting longer. This is just a precaution to assure the neck mouth does not run out of clearance in the die. YMMV] Then relube afresh, both neck and body. Debur the mouth and resume forming.

3. Use a RCBS precision mike to begin measuring shoulder set back when the shell holder nears the die bottom. I shoot for zero to -.003 (SAAMI 1.630 shoulder to rim) and stop there. Any precision mike for the .308 case form (.243, 7mm, .308, etc.) will work for this measurement.

4. Now install and set the expander stem and the die height so that the expander opens the neck, the decapping pin just pushes out the old primer (if these are 1X cases), and the neck does not reenter the neck reducing section of the die. Make sure the expander ball is cleaned and well lubricated with RCBS-2 before installing. This takes a little experimenting to get set correctly, and requires some tactile feed back on the ram handle to feel with the expander is working or running clear.

5. Remove the case, and trim again.

6. Now there is an internal ring of brass material built up inside the case at the junction of the neck and shoulder. Also the neck is extra thick, but has been formed out to "almost" the correct ID by the expander ball. Most of the thicker neck material is now on the outside. In order to control neck-to-bullet tension and assure proper clearance of the neck and chamber, the neck must be turned. RCBS has a neck turning attachment 98861 for the various calibers. It consists of a neck inside diameter reamer and a neck peeling cutter that work simultaneously and retrofit into their RCBS trimpro. I plunge and reverse the reamer and peeler two or three times to clear the turnings. Also clean and relube the shank of the reamer to reduce turning friction and torque.

The key is keeping the expander stem out of action during the neck forming. The neck gets thicker and the die and expander will not work simultaneously with that extra brass thickness.

 

[counterclockwise]

Just finished developing my technique...


Dupe

 

[243winxb]

counterclockwise, was it worth all the trouble? LOL

 

[counterclockwise]

Was it worth it? ? ? ?

.
Of course. Have you tried to price Lake City, Once Fired, 7mm-08 cases lately?

On the other hand Wideners has bunches of those used Lake City .308s at good prices.

 

[MCMXI]

First off, thanks to 243winxb, freakshow10mm, interlock, ranger335v, GooseGestapo and counterclockwise for the excellent comments. I've been reloading since '92 but have never had to size a case up or down so your thoughts and experiences are very helpful.

Interlock, the 139 SSTs are for sheep at 250 to 350 yards and ~z has had good results with them. I have zero experience with hunting bullets so all I can do is trust knowledgeable folks like yourself and ~z. I'll definitely let you know how they work though. I'll be using a 150gr InterLock SST in my .300WSM on the same hunt.

I will say for sure that I'm going to run some FC cases through the FL die. I haven't ordered any supplies for the new rifle yet but will be ordering a bunch of stuff today. counterclockwise, you seem to have a very well thought out procedure there so thanks for sharing that.

was it worth all the trouble?

This is an interesting comment. If I had just bought a 7mm-08 rifle and didn't have any .308 Win brass, there's no way I'd be ordering .308 cases just to neck them down to 7mm. However, for many like me that have .308 cases in abundance, it seems like it'd be worth it. Admittedly it's not as easy as buying 7mm-08 brass to begin with, but I'm sure it's satisfying on a number of levels too. If you think of it as being a chore then it may not be worth it ... if you enjoy the idea of putting good quality, unused cases to use, and enjoy the challenge and satisfaction that comes with reloading then I'm sure it IS worth the trouble. I might have a different opinion in a few weeks though ... ... but I doubt it.

 

[243winxb]

1858, if you could do the process 1 time and done, maybe worth the bother. But the donut has been know to return after a few firing, at least when i have sized 308 to 243win. Do this simple test, a bullet should fall into the fired case. If it doesnt, the donut has returned. If you dont seat the bullet real deep, not a problem.

 

[MCMXI]

Do this simple test, a bullet should fall into the fired case. If it doesnt, the donut has returned. If you dont seat the bullet real deep, not a problem.

Thanks for the tip ... I'll definitely keep an eye out for that. Hopefully the .308 to 7mm is less problematic compared to 308 to .243.

Thanks.

 

[MCMXI]

Would it be possible/advisable to use a .308 neck-sizing die (Redding), with .326", .317" and .310" bushings to reduce the neck of .308 cases in approximately 0.009" increments from .335" O.D. to .309" O.D.? This would be done after FL sizing using a Redding FL .308 die. Also, I would think that a .308 seater die and a .308 body die would work on 7mm-08 cases too since the body of the case has the same dimensions as the .308 Win.

It's odd that Redding sells separate 7mm-08 neck-sizing, seater and body dies since .308 dies should work fine right ... with the right bushings of course. I suppose it's easier (and more profitable) to make new dies rather than add .308 Win/7mm-08 to all the .308 dies. Am I missing something?

 

[243winxb]

My Redding FLRS type-S busing die does not size all the way to the shoulded in 243win. There is that tiny area when the body die part and the bushing does not touch the brass.