7mm/08 1:11.5" twist

[Con]

-- Temperature definitely will affect stability. The higher the temp, the easier it will usually be for a bullet to stabilize. A bullet that is "stable" at 120F. may very well not be stable at -40F. OUT OF THE SAME GUN, WITH SAME AMMO!


Interesting point! Barnes sell their 44cal 300gr Barnes Buster with no mention of the 1:20" twist warning on the boxes. A bit irrate (I have a 1:36" 444Marlin) I emailed for clarification ... had a response that they have yet to conduct cold weather testing on that projectile. Once cleared of stability issues, the 1:20" warning will be deleted.
Cheers...
Con

[diriel]

You may get lucky and have it stabilize, but I have a feeling you will run into problems on this one. I would like to hear how it works out for you. Aprox what elevation do you plan to use it at? And about what temps? Even being optimistic when I ran the numbers for that bullet in that twist, it came out looking iffy at best. The 20 twist on the other hand looks like it will stabilize it fairly well even down into the negative temps.


Have a good one,
Gary

[Con]

FYI ... the take-off 7mm/08 Stevens barrel arrived today. Despite being purchased new a few weeks ago here in Australia, the rifle was an older stagger feed model.

Barrel is definitely a 1:9.5" and has the poorer external finish reminiscent of the earlier Stevens 200s.

diriel,
Vast majority of hunting in Australia is undergone at under 1500m elevation ... more like between 100m and 1000m. Our Alpine temperature are mild compared to yours bottoming at about -10degC (it can get colder!), but it feels colder due to higher humidity levels. Most hunting is conducted at between about 0 degC and 15 degC on average. Up North however, it can be closer to high 20degC to mid 40degC. ;D
Cheers...
Con

[shovelheadave]

Any of you ever hear of JBM?


Yes, I use JBM, very handy.

[hotbrass]

That's great new CON!

Now you can go shoot that elusive OZ Elk! ;)

[xr650rRider]

This is put together by Bryan Litz.

Bryan Litz did NOT create any of those calculators. The stability calculator is from Don Miller. The creator of the JBM ballistics is James B. Millard. Litz came up with the G7 ballistic coefficients for several bullets. You can run the bc conversion program on JBM site and put in 1785 fps as average velocity and convert nearly every published G1 bc and get Litz's G7 bc.

Has anyone else had trouble buying Litz's book. I ordered it off of his website on 9/12/10 and still haven't received it. He answered one email saying he was in Australia until 10/19 and would ship upon his return, still nothing. Wouldn't have thought he was a deadbeat.

I bought one of the Stevens 200 for $179.00 from Academy when they were on sale and the 11.5" twist barrel stabilizes 140 Nosler ballistic tips and Accubonds just fine. Shoots the 120 grain ballistic tip very well as well.

[hotbrass]

I bought one from Litz in the summer and it was delivered fast.

And I bought one from Powder Valley for a friend for Christmas. But if you buy from Powder Valley, call in your order or they will charge $12 for delivery. I fell for it, but want to warn everyone.

[diriel]

xr650rider,

Please note that i said PUT TOGETHER BY.....not made by, not created by....hell for that matter if you simply click the JBM link and look you will see bryan say time after time Who did what and that he simply put it all in one place. I am well aware who made what. I am also aware who put it all on one nice easy page, with due credit to the respective authors ect.

Have a good one,
Gary

[xr650rRider]

I guess I'm dense as I interpreted what you said is that Bryan Litz created the JBM website and put all the calculators in one place.

(JBM=Jame B. Millard)

Not arguing but I know how much work is involved and hate to see credit go to wrong person.

[mctjeep]

I just shot my stevens 200 with the 1:11.5 twist, and it shot like crud with factory federal load with 140gr. ballistic tips. Groups were 3"+.

I even pulled the scope off and stuck it on my 6br to make sure that wasn't the problem. 139-140gr is about all i can find around here and i didn't really want to start reloading 7mm-08, so I pulled the barrel off and replaced it with a 243win barrel i had laying around. I know it shoots decent.

NOT impressed with the twist. ???

[DGD6MM]

I still stand by my statement, because I know I'm right. ;D I live in Florida, it doesn't get much more closer to Sea Level then here. ;D I've tested stuff like this before and been satisfied to the point that I did not hesitate selling the 1-9.5. ;D I live by the proof is in the pudding. ;D I've never been a user of Barnes Bullets, and don't plan on being. ;D I've killed plenty of game with all types of bullets other then Barnes, DEAD IS DEAD... ;D I'm glad I'm not book smart. ;D

[Con]

That's great new CON!

Now you can go shoot that elusive OZ Elk! ;)


Damn it man ... will you keep quiet! I can tell you with nil authority ... there have been no Elk shot in Nth East Victoria at all ... and there are none at taxidermists being mounted currently. ;) ;D
Cheers...
Con

[xr650rRider]

I think these were stable. Pretty decent for a $179 rifle with Nikon Buckmasters 3-9x40 scope that I got for free.

120 grain ballistic tips.
http://home.windstream.net/linngl/images/SAM_0348.jpg

http://home.windstream.net/linngl/images/SAM_0351.jpg

140 grain ballistic tips.

http://home.windstream.net/linngl/images/SAM_0349.jpg

http://home.windstream.net/linngl/images/SAM_0350.jpg

[DGD6MM]

That's what I'm talking about! I let most of my talking be done on the range. Nice groups.

[Cycler]

OK, some 11.5" twist barrels shoot well and some don't but the twist is marginal at best for anything 140 gr and higher. There is still no explanation for why Savage went to the slower twist as 9 to 9.5 is universal among almost all other barrel makers for 7 mm rounds. What possible benefit does it have?

[diriel]

Hey rider, no problem on the credits thing. I know what you are talking about.

Folks, here is the deal: I shoot primarily Spitzer Boat Tail bullets. Now a lot of your SPBT bullets are either Too long or right on the edge of too long in an 11.5 twist barrel. Now, a Flat base or very mildly boat tail bullet, like for instance a Nosler Partition is not too long and will in fact stabilize decently.

Bullet Length: .284 dia
-- 140gr. Nosler Partiton = 1.160 (Not too long for an 11.5 twist.)
-- 140gr. Nosler Ballistic Tip = 1.315 (Too long for an 11.5 twist.)
-- 140gr. Berger Hunting VLD = 1.018 (Not too long for an 11.5 twist. Berger states it requires an 11 twist to stabilize.) The 168gr. Berger will NOT stabilize in an 11.5 twist.
-- 140gr. Barnes MRX BT = 1.190 (Stable down to about 20deg. F. This is about as long as I would go in an 11.5 twist barrel.)
-- 140gr. Barnes TSX = 1.267 (Not what I would call really stable, but might maybe work. I would not throw my money away on it however. Too expensive for a Maybe. This is the type of bullet I would want for something like Alaska, but would suck there in the lower temperatures that I would likely get caught in.)
-- 139gr. Hornady BTSP Interlock = 1.153 (Stable enough for general purpose hunting, for me.)
-- 139gr. Hornady Interbond = 1.291 (Not what I would call really stable, but it may work for you under near ideal conditions @ 20deg. F.. I use 20 deg. F. as my upper low temp point. For me, I would not take this load to Alaska. But for Florida it may work ok. Maybe. I would not bet on it however, and would not personally load it in an 11.5 twist barrel.)
-- 140gr. Sierra GameKing = 1.160 (Good to go.) This is the heaviest Sierra I would use in an 11.5 twist barrel.
-- 140gr. Speer TBBC-SP = 1.150 (Good to go.) In fact with Speer especially, even up to the 160gr. will usually stabilize for you. Just stay away from the BTSP and you are good with the heavy 160gr. Speer's.

Ok kiddies, so we see that my prejudice for long BTSP bullets colored my thoughts a little on an 11.5 twist. I still say that for me, screw the 11.5 twist! I shoot a lot of Barnes bullets, I live in California. I also have a very good hunting nut friend who owns land in Alaska, and get to hunt there once in a while. For me, a 7mm of any kind makes me want to reach OUT and have fun with all the great ballistics of the 7mm. So for me, an 11.5 twist barrel would suck monkey balls. The first thing I would do is load up some 168gr Berger VLD's and go out to stretch the 7-08's legs, which of course would not work well at all. Then of course I would load up some 150gr Barnes TTSX. OOPS! That don't work for crap either!! DAMN!! hahaha :)

These are just my thoughts on the matter, but I would most definitely not throw good money in the garbage on an 11.5 twist 7mm. If you plan on going to a light bullet, there are simply better choices out there. Life is about trade off's. For me, if a bullet is going to be short ( low sectional density ), then it is going to be blunt and heavy to make up for that.

Good hunting folks,
Gary

[hotbrass]

Now that right there is a good post. Great stuff!

Thanks diriel!