Chamber neck is 0.315"+. Federal GM 308 cases necked down. Loaded neck is 0.315". If not, what components are you using? Thanks. Ron.
Do YOU have to turn 7-08 necks?
- Thread starter benchrester
- Start date
Well, what's the rule of thumb?
.001" clearance at a minimum (on each side of the neck) ?
Chamber equals a delta of .315"+. Loaded round equals a delta of .315". Doing the math, I'm not seeing that clearance.
You will need to turn those necks, is my best guess.
Chris
I am just surprised that a factory SAMMI chamber will not safely fire commercial brass. I assume factory, because the fired necks measure 0.316". That's a first for me. A couple other 7mm calibers I looked at have 0.320" necks. Is anyone out there NOT having to turn?. If not, what brass are you using? I turned necks to 0.312" and it doesn't have the fliers as with unturned. I am using Hornady 162 Amax. A flat base bullet could have a larger base diameter. Thanks for the replies. Ron.
I always read that the neck of the 708 should not be any bigger than .315" once it's reloaded.
NP Flight, kinda figured that. I purchased the rifle this spring. Was built by Shilen in 1979. I don't have a problem with the tight factory neck, esp. Whole bunch better than some chambers that are 0.10" larger than loaded diameter. Just surprised it is so close to factory cartridge dims. Thanks. Ron.
Just read a post here necking down, thick. Necking up, thin.
I just load Win. 7-08 hulls with 162 Amax and get .310.
I just load Win. 7-08 hulls with 162 Amax and get .310.
benchrester said:
You are?
7mm-308win (the cartridges you're loading) and 7mm-08 Rem (the chamber you've got) aren't exactly the same, as one complies to a SAAMI standard and the other does not.
SAAMI specifies a minimum chamber with a .316/.317" neck .317" at neck/shoulder and .316" at the casemouth. It sounds like your chamber is SAAMI minimum.
A friend has a Criterion prefit chambered in 7mm-08 with SAAMI minimum neck, and we also had to neckturn FGM 308 brass in order to use it.
If you buy Winchester or RP headstamp 7mm-08 brass, you'll find it's loaded neck diameter is ~.311-.313"
So, in short, the direct answer to your origninal question is "yes".
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I think I have several problems with my set up. Like thicker neck FGM 308 brass, which ends up even thicker when necked down, and quite a bit shorter than 7/08 spec. My barrel has 7mm 308 on it. Maybe it is diff. than the newer 7/08 version. I was going to neck down some Lapua 308W brass I have, but now I think better to go with real 7-08 brass, or neck up .243 brass, or fireform .243 brass out to 7-08. Will have to start searching for some 7-08 brass. Thank you all for the great tips. Ron.
In 1979 the round was still a wildcat IIRC. You, most likely, do not have a SAMMI spec 7mm08 chamber. And, for the record, I have only had to neck turn brass when I necked up Lapua 260 brass for 7MM08. That was not worth the effort (if you are curious).
I am thinking the SAMMI spec 7-08 had the .316 to .317" neck. Can't seem to bring it up to look again. That was in 4/80 I think. I have a dim from Sierra for 7mm-08 Remington, .315". Also Wiki same. Do these agree with your interpretation? Was the later, after Sammi in 1980, changed to tighter neck? As my bbl shows, 7-308. The buyer got it in 1980, when I called Shilen they said it was made in 1979. Neck meas. .316 after fireing. This is not clear to me what I have, doesn't mean beans really. Just interested in it. Shot this .3" four shot grp yesterday at 100yds, so not complaining. MUCHO workups, etc. to get there. Used neck turned FGM brass, .311" ND. Search for 7-08/243 brass, but ones I saw were OOS. Thanks. Ron.
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I use once fire LC military brass in my .308 and 7mm-08 I neck turn both. I set up my turner to take a very minimal cut. Load a bullet in the case it chamber easily you are g2g no "need" to neck turn. If you got the tool use it. An AR with an 20" barrel in 7mm-08 is my current itch for steel matches. Plus it's beat switching my savage barrel all the time.
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