Tee Vee

Everyone probably has had a moment of frustration when working on a project and that's where I am right now. Purchased a Savage Axis in 7mm-08 last years Black Friday sale in Winnipeg, MB. The facts so far: (1) On a 200 yard sight in target a box of Remington 120 gr. pretty much covered the target. (2) Remington 140 gr. gave about 1 1/2 inch group again at 100 yards. (3) Tried IMR 4064 with 139 gr. Hornady and at well below MAX load in Hornady manual blew primers several times to the extent that it blew away the extractor bearing. (4) Switched to Varget and no blown primers until this week testing Hornady SST 139 gr. in Imperial .308 casings necked down, annealed. (5) During testing for the 139 gr. SST on Wednesday, at the 39 gr. load the grouping blew wide open and at higher charges right off the target. I tested up to 39.9 gr. of Varget as pressure signs were acceptable at all tested loads.

I have begun to think it might be possible to require a heavier bullet but for the fact that commercially made ammo isn't loaded heavier. Any thoughts or suggestions for me to consider/try folks?

UncleNorby

Excess pressure can be the result of lots of factors. You might consider making a cast of your chamber, just to see where it is in comparison to specifictions. "Tight" chambers can cause pressure.

Also consider shooting only reloaded 7/08 brass, or perhaps sizing up from 243. That way you're sure not to have case necks that are too thick. Just because a round will freely chamber, does not mean it won't cause a pressure spike.

You don't say what your OAl length is, but assuming you're not doing anything strange, that should not be the issue.

How does you case volume compare to the case volume of the loads you are using for data? If your cases are smaller in volume in comparison, that can cause pressure.

Are you using the same primer as indicated in the data?

Just some random thoughts, hope you figure it out and get it to shoot.

alleyyooper

I load 120gr. Hornady A max bullets over IMR 4350 with good results.
But I shoot them from a pair of Remington rifles a model 7 and a 700 mountain rifle. I personally would buy a 100 rounds of 7MM o8 brass.


Al

Ridge Runner

at 39.9 gr your still below the min. charge of 40.5 gr, read up on using below min charge of slow burning powders, below min loads will exibit pressure spikes as bad if not worse than overloaded.
Hodgdon #27 lists a min load of 40.5 gr with a 139 gr hornady and a max load of 43.5 gr.
if your not against the lands, you are having pressure spikes from underloaded rounds.

Due to all the liability in todays society, the chambers on most rifles are cut pretty generously, that means a min.load in a test rifle will be more prone to pressure spikes in a rifle with a slightly larger chamber, if it were me I would load 41 gr and try a round in a once fired case, measure casehead expansion, go from there.
are you blowing primers (expanding casehead) or piercing them? there is a difference
RR

gonetocamp

I load Varget in two 7mm-08s. Browning Abolt II likes 40.0 grs. and Rem. 700 SPS likes 42.5 grs. I load Sierra 130 gr. HPBT MK. The Browning and the Rem. also like different OAL.

Tee Vee

Thanks for the responses everyone. So far I have used my dial callipers and verified case measurements in the Hornady Manual 9th Edition and aside from being a bit short all readings are within 0.001 inch so far. Wall thickness on the Imperial .308 casings is in the range of 0.012 to 0.015 inches and a check of 7mm-08 Remington casings yielded a consistent reading of 0.012 inch. Will load up 139 SST gr. test loads in RP 7mm-08 casings and test this week.

Ridge Runner

start midlevel around 41 gr. trust me, been there done it on more rifles than you can count.
RR

bpd1982

I have great groups with my 7-08 with 140 TSX and 47 Gr. H4350. I never could varget to shoot with any bullet.

bronko22000

I think there may be a problem with you using the necked down 308 cases without turning them. Have you tried reloading the factory cases you fired off?
It could possibly be the bullet weight. I have two 7-08s. My Browning shoots the 139 gr Hornady Interlock spire points very well but does not like any 154 gr bullet. My Savage is just the opposite. It shoots the 154s like a champ but will not group 139s worth a darn. Both have 1:9.5" twist rates

Tee Vee

Hi everyone. It's been a few days and I've been busy for sure. I got in a bit more at the range with the 7mm-08 and it's amazing how groups changed from day to day. I believe that the necked down 308's difference in neck thickness played a factor as factory casings did indeed give better groupings or should I say MUCH Better and with that a lesson was learned.

Here I am now without the 7mm-08 as between my back and right shoulder the pain was increasing. In the end my friend gave me a reasonable price for the 7mm-08 and I invested in a Savage 11 Lightweight in 260 Remington. Cabelas only had a few boxes of Remington 140 gr. Rem. so I bought two to get a feel or comparison. I found the lead tips to be deformed a bit but used them anyway. The result I found what I expected in that the muzzle blast was noisier and recoil more tolerable on my shoulder after firing forty rounds in about an hour. Yesterday I picked up six boxes of Nosler Partitional 125 gr. for a good price as that is the weight I wanted to use. Next is a set of dies and away I'll go loading light target loads for it.