HELP! 7mm-08? Case sizing difference?

[lak]

I'll try to make this quick. This is my first bottle necked rifle. I just got a new custom Encore barrel that will chamber new ammo just fine, but will not chamber once fired resized brass. I'm using an RCBS set of dies. New ammo measures .462 just above the ejection rim. Once fired brass, that has been resized measures .470 just above the rim. Is this normal? did I get a bad set of die? Is there a difference in die by manufactor? Is there a manufactor that runs smaller. HELP!!!. Lak

[bobthenailer]

First was the brass that doesent fit orgionaly fired for the first time in your firearm ? if not the chamber may of been bigger than yours ! you may have to use a small base sizer ! you could use one from a 308 or 30/06 with no special procedures as its 308 bullet dia and yours is 284 dia.
IF not you may have a oversized chamber ! or there my be something that your sizer die is oversized
ON my single shot pistols i only partial size or neck size my brass

[kenyerian]

Here's a link to the dimensions that list's the base at .470. http://en.wikipedia.org/wiki/7mm-08_Remington. Looks like the dies are standard. Did you check the case length? might need trimmed. What is the OAL of your reloads? I think I would call the manufacturer and talk to the smith that reamed your barrel and see what he suggests.. I reload a 7TCU and the dies have to adjusted very carefully . Try checking the shoulder .

[**oneshot**]

If the above mentioned is correct and your using fired brass from the same chamber:

Try indexing your brass. Mark a case on the base, put the mark at 12o'clock in the chamber. Fire it. Take the case out wipe clean as to not remove the mark. Resize and see if it goes in with the index in place and with the index elsewhere. If it only goes in with the index in place, then you have a chamber problem. Had it once in a 308, brass would only rechamber on index. I sent it back and got a new barrel.

[dragonrider]

One other thing, try annealing the brass and then full resize.

[Lance Boyle]

-another frequent sneaky buggaboo with bottleneck cartridges is a tight pull through the neck with a large and or gritty expander. It can pull the shoulder out of shape and give you a longer headspace. If your expander did not come out smoothly you may very well have this issue.

That fix would be to polish the expander with some very fine sand paper, crocus cloth, or steel wool. (Those go from most aggressive to least aggressive metal removal/polishing)

-you could do a cerrosafe casting of your chamber to get your measurements to help you analyze the issue.

-most normal dies will not touch the lowest half inch or so of the brass. You'll see a definite demarcation line where there is no die scuffing. That mark is commonly mistaken for an incipient headspace seperation but a quick check is to look on the inside with a sharpened paperclip for a catch on the corresponding interior surface. Just drag the sharpened paperclip up from the base toward the shoulder, shouldn't grab anything.

[1hole]

Most failure to chamber problems are due to a failure to adjust the FL sizers down far enough. Forget any 'instuctions', they only get you in the ball park. Set up and size as you did at first and, with the ram fully up, look under the die and see if there is an open crack between it and the shell holder. If there is, adjust the die down until it's closed, then you should chamber fine.

The effort required to extract an expander seems like a lot it really doesn't amount to much. Stretching cases with an expander ball is a common idea but it really doesn't have much effect; the soft neck metal will easily expand before the shoulder moves and the neck itself sure won't stretch.

[lak]

Thanks guys for chiming in and sorry for the late response, really no excuse for that but just kept putting it off. A little knowledge is dangerous I guess that describes me on this subject. Here’s the gig, I ordered a 7mm-08 Encore barrel with a 1-12 twist. Some may disagree with the slow twist, but Husqvarna made a model 4100 with a 1-12.5 twist. Owners state it will shoot it will shoot 150 grain bullet. So now to the problem, it will not chamber once fired 308 brass that has been resized to 7mm-08 specs that measures .470 at the base. But it will chamber new 7mm-08 brass that measures .464 at the base. The chamber measures .468, The brass is clearly marked where it is rubbing up against the chamber. It will chamber new brass reloading with lead bullet, the throat is long enough and with bullets sized to .285 it is a very tight fit. I realize the brass will swell once fire to the chamber dimensions. One concern is once that brass is ejected, will it grow to a size that will not rechamber. I email the manufactory about this situation and the response was the barrel was chambered for new brass and once fired brass could not be used. I didn’t realize this when I placed the order. RCBS list dies that have a smaller base but haven’t found the dimension on line yet. I’m thinking of taking a old 44 mag die and some lapping compound and honing it out using 308 brass until it get close to that dimension and then finishing it off with 1000 grit sand paper. What say Yee…..Lak

[lmcollins]

Are you trying to chamber a loaded round, or just a fired and sized case?

Try chambering a resized fired case without a bullet seated. If you are resizing fired 308 cases you migt have an instance of tolerance stacking. The 308 case neck might just be thick enough over a 7-08 case to make a minimum dimension chamber neck with a bullet seated too large to seat.

If you are trying to chamber a round loaded with an oversized cast bullet of say .286 into a already tight neck situation you are even more screwed, and the neck of your loaded round would be more oversized. Measure a loaded factory round neck, and then compare what you are trying to chamber.

Also, remember: you check overall case length AFTER sizing your case. When you squeeze it down in the die the excess brass goes up the neck of the die, makeing the case longer. Check your case lenght after sizeing, and befor chambering.

Now you have several things to check. Wish you were here for me to go through it with you!

[FLINTNFIRE]

Had a 300 win. mag. would chamber factory fine , but not full length resized , needed the rcbs small base full length size die , solved problem , tighter cut chamber on that gun then on most

[lak]

Barrel will not chamber resized UNLOADED 308 once fired brass. It will chamber new 7mm-08 brass that has had the orginal bullet pulled, and replaced with a lead one sized to .285, its a tight fit. Brass length is not the problem. I had one round of empty brass measure .468 is a snug fit, .470 is just to big. Looks like I need a Small base die.....Lak

[lmcollins]

Again: you may have another kind of stacking of tolerance issue.

You might have a deap die, and deap shellholder. The result of this is that you are not moving your shoulder back far enough when you resize. Remember that the sizeing die does not size the bottom of the case which is held INSIDE of the shellholder.

Take something like a fired 45acp case and place it on top of the neck of the two cases and measure them from case head to case head with caliper. (I think a 45 case is long enough. IF not use a 38 case.)

You might find that you just need to have someone with a lathe take a carbide tool and face a couple of thousands offf of your die or shell holder. The shellholder is cheapest, so try it first.

You can place the shellholder face down on some wet-and-dry paper or abrasive cloth on a flat surface and shorten it by polishing it down.

[runfiverun]

Barrel will not chamber resized UNLOADED 308 once fired brass. It will chamber new 7mm-08 brass that has had the orginal bullet pulled, and replaced with a lead one sized to .285, its a tight fit. Brass length is not the problem. I had one round of empty brass measure .468 is a snug fit, .470 is just to big. Looks like I need a Small base die.....Lak

yep.
you could also send some fired cases to a die maker and have them do a custom die set.
probably be close to 300.00 dollars though.

[shotman]

you can NOT size 7mm-08 from 308. Unless you ream the neck . Forget the 308 cases and order 7mm-08 new cases
Its the same as tring to make 270s out of 30-06
You expand up but not size down

[lak]

You guys got me thinkin. Here's what I did. I took an unloaded military 308 round stuck in in a drill, neck first. Used 120 grit sand paper to remove some of the base until it got to .468 or a little less. That round would fit in the chamber, no problem. Then loaded a RCBS 145 Sil bullet sized to .285 in the same round using the standard die. It will chamber the barrel, the last 1/4" is a snug fit. Length is to specs.

[GabbyM]

Have you tried removing your 7mm neck expander button then sizing a 7.62mm case with no neck expansion? This will tell you if you are getting the body and neck sized down initially. If that case chambers then you know you are sizing it enough. Then as has been mentioned you are either pulling the shoulder forward with the expander ball or your necks are to thick or both as thick necks will increase pull on the ball.

With oversized cast boolits and necked down 308 cases you are about sure to need a neck turning tool or reamer.

[lak]

Problem is fixed guys. I ordered a Redding SMALL BASE 308 sizing die and unscrewed the deprimer stem. Sizes brass now to .468 at the base. Once fired 308 brass reloaded with bullets sized to .285 with a slight crip chamber snugly. Some military brass works as well, but some have a slighly wider rim, a file and drill fixes the problem easily. Some military bass has thicker brass at the neck and is difficult to chamber. Could of gotten by with just a body small sizing die, but 308 is the next gun on the wish list. Thanks for all the inputs

[Harter66]

For what its worth . I've 3,30-06's each of them have some unique thing about them that prevent them from sharing brass . 1 has a fat shoulder,another is fat all over except the shoulder and neck. The last 1 won't even take its own brass back w/o being 100% full lengthed. Either of the other 2 are happy w/a half neck size for brass to its gun. If I size the brass for them to w/in a .1 of 100% they will share but both are firm to close.

The picky gun oddly shoots the worst groups and is the most expensive of the 3,if it were to be replaced.

[GKB22]

Glad U got it fixed, that was some really interesting replies, a lot of good info