Thread: Some new calibres for custom builds

I had an interesting day at the range yesterday, I had four unfired rifles, three of them with calibres most likely unfired in NZ before ?

All the speeds quoted are from a Oehler 35p & are approximate at this stage until the rifles are finished, fluting etc & I use my pressure testing gear to get final safe/conservative pressures/velocities.

The first was a 280ai on a T3
162s going 2850-2900 with 20-21" barrel, recoil with the T2 muzzle brake was almost non-existent

Then I fired the 6-204 Ruger, once again a T3 with a Trueflite barrel std 22" T3 profile.
75 V-max at 32-3300
80 Gmx at 31-3200
87 SP at 30-3100
I'm very happy with this rifle it wants to shoot sub 1/2moa & with less than 30grains of powder it goes very well compared to a 243 & would be very quite suppressed

The 7-375 Ruger was next Rem 700 SPSS 25.5" barrel with T2 brake.
75-85 grains of powder.

162 A-max at 32-3250
180 Hybrid at 31-3150

Then finally the 30-375 Ruger Rem 700 SPSS 26" barrel with T2 brake.
75-85 grains of powder.

208 A-max at 30-3100
230 Hybrid at 29-2950

The 375 Ruger cases are showing great promise, with performance between the 7mmRM & 7mm Rum and 300win & 300 Rum

Burning a relatively small amount of powder for the velocities achieved should mean they last substantially longer than their bigger cousins.

I will post pictures & more info when I finalise them, cheers.

Very nice greg and no offense intended but can I ask why? Theres much more standard and easily formed cases that will do similar.... With exception of the low powder use of ur 6mm~204 ruger... ok much less overbore and more bbl life... But I struggle to see how the likes of a 7_375 ruger will catch on when a 7stw already more than holds such a niche in a much more easly acheivable end result????????? And ditto ditto... And you urself are the one who talked of the like of mr duley and his custom calibres and ransom of reamers.... A case of mouth in foot here I feel.....

Hahaha great mindes think a like here Greg.
On saterday while I was trolling the net. I camw across the 7mm-375r and it defently cought my attention.

Originally Posted by baldbob

Very nice greg and no offense intended but can I ask why? Theres much more standard and easily formed cases that will do similar.... With exception of the low powder use of ur 6mm~204 ruger... ok much less overbore and more bbl life... But I struggle to see how the likes of a 7_375 ruger will catch on when a 7stw already more than holds such a niche in a much more easly acheivable end result????????? And ditto ditto... And you urself are the one who talked of the like of mr duley and his custom calibres and ransom of reamers.... A case of mouth in foot here I feel.....

Thanks for that Adam.....
Please define similar.....
How many STWs are there out there......
The STW won't fit the standard magazine, uses more powder & has a belt....
Search the net on 7mm 375 & you will be very supprised.
The brass is very easy to form with standard dies...to easy......... not quite as easy the Edge brass...
My brass won't be $10 a go either, ever & you will be able to get it when YOU want it, you can make it yourself..

Well a 243 will eat a 6/204 for dinner!!!
Abe gets more for less on a stw and whats a belt got to do with the price of cheese?
Also the 30cal doesnt stand out either theres calibres much more run of mill which will do the job...

Im just saying these calibres offer us very little in regards to whats already available...

Very nice and very cool but a little constructive critisisim never hurt anyone

And you yourself said... You wanna play you gotta pay!

Originally Posted by baldbob

Well a 243 will eat a 6/204 for dinner!!!
Abe gets more for less on a stw and whats a belt got to do with the price of cheese?
Also the 30cal doesnt stand out either theres calibres much more run of mill which will do the job...

Im just saying these calibres offer us very little in regards to whats already available...

Very nice and very cool but a little constructive critisisim never hurt anyone

And you yourself said... You wanna play you gotta pay!

You got cabin fever again ????......remember what happened last time........

What happenened last time, that has anything to do with me asking u a few basic questions about what your really offering???? When you havent answered my question at all!!! Your just poking it to the side... I love it how you always contradict yourself with what you say down the track

Originally Posted by baldbob

Well a 243 will eat a 6/204 for dinner!!!
Abe gets more for less on a stw and whats a belt got to do with the price of cheese?
Also the 30cal doesnt stand out either theres calibres much more run of mill which will do the job...

Im just saying these calibres offer us very little in regards to whats already available...

If we all thought your way Bob, we would be shooting 303, 30-06 and 8mm mauser...

Originally Posted by baldbob

What happenened last time, that has anything to do with me asking u a few basic questions about what your really offering???? When you havent answered my question at all!!! Your just poking it to the side... I love it how you always contradict yourself with what you say down the track

One of the most important things people wont when thinking about getting a 7mmSTW is will it fit a standard mag, the short answer is no, the 7mm 375 R dose this easily with the long pills using just a little less powder for the same velocities, I would say that is a big advantage.

While the 30-375 isn't as fast as the 300 Rum it easily beats the 300 win and is about the same as the 300 WB, but again its big advantage is it will fit in a standard mag with the long pills.

The 6mm 204 is a great little round that sits well between the 223 and the 243 and would be great for a young hunter or lady wanting to shoot a low recoiling rifle, it only uses 28-29 grains so that tin or powder would go a very long way. Someone using alot of rounds goat shooting might be very interested in this round.

Back in 1994 when I had my 7mm STW built the g'smith offered to build a 7mm on a 375 case but I had my heart set on the STW otherwise I would have had one.

Originally Posted by baldbob

What happenened last time, that has anything to do with me asking u a few basic questions about what your really offering???? When you havent answered my question at all!!! Your just poking it to the side... I love it how you always contradict yourself with what you say down the track

I see "Angry Bob" is back, just look at your posts over the last few days....

The 243 does eat the 6-204 & so it should with with around 50% more powder depending on the load.


ADI 243, 85 AR2209 24" 45.5 C 3215, the 6-204 with 22" barrel & is pushing the 87 less than 200fps slower with 29grains of ADI powder....

I don't know about Abes STW & loads but it looks to have a barrel longer than 25.5", I may be wrong, so comparisons there are mute.
The data I have managed to find is that the STW performs around the same as the 7-375R with slightly more powder in a longer case that isn't std magazine compatable with the 162s & 180s even with a short throat.

I managed to get around 3200fps with a 208 out of a 300Rum Sendero with 13 grains more of the same powder for 175 more fps than the 30-375R & it wouldn't fit in a std magazine......
I'm not sure how fast the 230 is going in the Rum but the 30-375 isn't too shabby at just over 3000.......with less than 84grains.
The 300win mag isn't close enough in performance & uses about the same amount of powder...

Originally Posted by Spook

Back in 1994 when I had my 7mm STW built the g'smith offered to build a 7mm on a 375 case but I had my heart set on the STW otherwise I would have had one.

I imagine that was a 375 H&H case which is very similar/or the parent case to the STW, I'm not sure off the top of my head ?

The 375 Ruger is a relatively recent factory case.

Very Interesting, I like the sound of the 280AI

As to why you would want to try something different, because you can!

YAWN

Theres very little thats new in the wild cat world. Many decades of inventinve shooters and tinkerers have expolred most nooks and crannys in the brass shape department.New devlopments in powders and projectiles revive interest in things sometimes .The 6mm-204 is a 6x47 federal (not the 6x47 lapua) with a different head stamp and the 375 ruger has been pushed and pulled since it came onto the scene some years ago. The 7mm LRM as one maker is calling the 7mm-375 R with a few tweaks ) interested me a while ago, if it would clean up a 7 mm rem mag chamber then it would make a nice cheap alternitive in a T3 or simmilar, like the .338 sin can be a rechamber on a .338 winmag giving a good performance gain for little outlay. Greg have you pushed the shoulder back on your version to gain a little neck length? Nice to know theres a reamer in the country