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7mm-338 thoughts
- Thread starter mlc0341
- Start date
Doing a long neck 7/300 Norma 35 degree improved.
300 Norma is easier to neck down to 7.
Have 2 guns being built. A reapeter and a mag gun. Mag gun will be light weight.
Pm if you need anything for help.
Also may do a 7/338 Laupa will see.
God bless
Jeff
300 Norma is easier to neck down to 7.
Have 2 guns being built. A reapeter and a mag gun. Mag gun will be light weight.
Pm if you need anything for help.
Also may do a 7/338 Laupa will see.
God bless
Jeff
I'm looking forward to the build I'm going to work the 7mm mag and step up as I go there is not a lot of data on the 7-338 right now I know it's coming.
Read up on Tom Sarvers 7mm Hulk, very similar to a 7/300Norma. Tom is a very friendly guy and will probably be happy to share his experiences with you. Shoot him an email.
There's not much info on the 7 hulk. I have tried to contact Tom over the past few weeks but no reponse.
Originally the cartridge was based of the lapua case but recently a Norma mag case is being used.
I'm interested in a 7 mm as well
Originally the cartridge was based of the lapua case but recently a Norma mag case is being used.
I'm interested in a 7 mm as well
I really like the performance of the 300Norma, my friend has one (that bastard!) and kicked around the idea of the 7/300NM but it is so ludicrously overbore. More than a few including Terry Cross are having fantastic results with the 7/300WinMag, I am leaning towards the 7/300WM myself. TresMon did a writeup a few years ago and his initial results were sub 1/2 MOA and IIRC around 3k fps with the 180 Berger. Food for thought.
I Will go 7/300 Norma (less overbore than a RUM) because mine will be a switch barrel. 338 Lapua uses the same boltface.
Love the 7mm for a great balance in bullet weight and ballistics. However, getting much above the 7 Rem mag is a barrel burner.
That said, I have been impressed by the number of cartridges that use a long freebore, much like the Weatherby's. When the barrel is very tightly toleranced they produce anywhere from .5 to 1 moa The best you'll get is a ragged hole. The norm you can get is more like five close holes. Again, holding somewhere around moa. I used to think moa wouldn't cut it, but for extreme long range it really isn't that bad. As long as the group is centered, you'll still see a majority of hits.
That said, I have been impressed by the number of cartridges that use a long freebore, much like the Weatherby's. When the barrel is very tightly toleranced they produce anywhere from .5 to 1 moa The best you'll get is a ragged hole. The norm you can get is more like five close holes. Again, holding somewhere around moa. I used to think moa wouldn't cut it, but for extreme long range it really isn't that bad. As long as the group is centered, you'll still see a majority of hits.
Just a note. Pure accuracy lives around 3000FPS. Maybe up to 3100. After that you need an improvement in other areas to offset the loss of accuracy. YMMV
Any chance you have a 7/300 reamer Mr Tooley? I'd be very happy with a Berger 180 @ 3-3100fps and moderate pressures.
You may want to look at a 7mm Practical (300WM necked down to 7mm). Once again, less overbore, pushing 180s at around 3100fps with H1000 or Retumbo. Brass is cheaper and more available than any of the Norma offerings, and you'll probably get a little bit better barrel life, though we may be splitting hairs with firebreathers like this. I've got a 7mm Practical coming back soon (LRI group buy) and would be happy to let you know how it turns out.
Quite overbore IMO.
A few observations with some friends overbore cartridges...the throat erodes quickly, then the bullet must be seated forward more to maintain accuracy, then after approx 400 rounds bullets start coming apart, I'm assuming from fire cracking. This was in a 6.5 pushing 130's and 140's at 3400 to 3500fps in long barrels.
Although it's not out yet the new 26 Nosler would be a good case size for a big 7mm. So is 375R BTW, a lot of necking down though.
A few observations with some friends overbore cartridges...the throat erodes quickly, then the bullet must be seated forward more to maintain accuracy, then after approx 400 rounds bullets start coming apart, I'm assuming from fire cracking. This was in a 6.5 pushing 130's and 140's at 3400 to 3500fps in long barrels.
Although it's not out yet the new 26 Nosler would be a good case size for a big 7mm. So is 375R BTW, a lot of necking down though.
I'm choosing the 300 Norma bc it will be simple to neck down. I don't want to have multiple steps and or fire forming to go through. Frank Green indicates Melonite is substantially (roughly doubling) prolonging barrel life. Mike Rock told me he really likes the process. I don't mind screwing a new tube on now and then. I plan to swap barrels and shoot a 338 Lapua off the same platform so I'm sure I'll use the 300 Norma as my base.
I dunno Dave, I've been really happy @ 2700 with my long barreled tight twisted 7mm-08 for accuracy. Good to a mile anyways.
I understand. The older I get I find I can do more with less. My comments were directed to those wanting a fire breathing dragon with a barrel life of 7-800 rounds. I started in about '93 using the 404 Jefferys case. No such animal as a Lapua or RUM in those days. 416 Rigby or the 30-378 case was all we had for a big case. Not many actions around to handle those cases. We used a 178 gr. Cauterucio custom bullet. Damn it was fun to shoot for awhile. 178's @3400 FPS . Brass didn't last all that long but when your rifle had a 1K yd zero on it you really didn't shoot it that much.
For the mentally unstable I have a 7-338 Lapua Imp reamer. Take a look at a 7-375 Ruger. I like that case size. You should be able to 3000+ FPS with that case. I have dies but only reamers in 338 and 30 cal. at the moment. I shoot a case based on the 8X68S blown out which has the capacity of a Win Mag and I get 3000 FPS with a 30" barrel on my target rifles.
Ahhh, the classic "Eargeschplittenloudenboomin-barrelenstorchen" (Stouckmeyer) Those were some fine rounds
Have done a few on the Norma case in 7mm all same design as shown.
3300 with 180 hybrids from a 26 inch barrel for a hunting rifle going to shoot a lot of animals/trophies so what's barrel life matter they are still making them.
7mm screamer (Norma imp)
6x47 lapua for size
7mm gonzo (based off the 300 Blaser mag case) will push the 180s mid 3150 out 26inch
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3300 with 180 hybrids from a 26 inch barrel for a hunting rifle going to shoot a lot of animals/trophies so what's barrel life matter they are still making them.
7mm screamer (Norma imp)
6x47 lapua for size
7mm gonzo (based off the 300 Blaser mag case) will push the 180s mid 3150 out 26inch
Sent from my GT-I9300T using Tapatalk
Attachments
I have a 7mm /338 35 degree improved. It has a longer neck for the big vld. Bought some 192 gr CE bullets very long. Want to throat the bore out so the bullet can be used on the driving band.
Needs a bit more twist 1-6.5 would be great only found a 1-7 Proof research barrel. Will try 1-9.3 Benchmark with 180 Bregers but do have some 200 Wildcats.
The 7mm XR has been used by a guy in Florida at the bench matches for a few years.
Run those babys hard as you can , barrels can always be changed. When you venture in this faster ,harder driven releam you know what will be the outcome. Fun Fun
God Bless
Jeff
Needs a bit more twist 1-6.5 would be great only found a 1-7 Proof research barrel. Will try 1-9.3 Benchmark with 180 Bregers but do have some 200 Wildcats.
The 7mm XR has been used by a guy in Florida at the bench matches for a few years.
Run those babys hard as you can , barrels can always be changed. When you venture in this faster ,harder driven releam you know what will be the outcome. Fun Fun
God Bless
Jeff
