100 Ttsx optimum rpm's

[Shoebox]

Hello all
Building a new rifle 25/26 nosler savage single shot, PAC nor 4 grove 1- 11 twist 26.5".750 at muzzel
Here are a few thing I would like to clear up
I'm building this as a 500y max rifle
Around ttsx -100 - 80 grn
After ordering barrel, a few discussions have come up about twist rate ?
I've research a few twist rate calculators
100 ttsx - 3700 =10.8. -3900 =11.1
80 ttsx - 3900 + 13.5
They are averaged on the 257 wby +25 stw, based on case capacity,
As I have not found info on this round
My 2506ai barrel has seen better days, so I decided to the something different this will be my last build,
Brass ? my only options are nosler or Norma, which brass would prefer for high pressure loads

Any comments or advice are welcome
As this is unchartered ground !

Steve

 

[TAJ45]

It seems there are more than a few who have found Nosler lacking when pushed.

 

[SheepDog]

I hope you are planning on using short, light bullets. 1:11 twist is too slow for heavy/long bullets. My 257 Roberts has a 1:9.5 twist and it is an "off the shelf" Browning.

 

[Shoebox]

Hi sheepdog
I had a few concerns over twist rate,
I have had a few conflicting results, I have had talk with some very experienced people, and and I value these opinions !
Twist rates from 8 - 12 , I have spent hours chasing info,
I'm only going to ttsx 100- 80 so that is what I based my search on
4 out of 5 twist rate and stability programs recommended 10.8 - 11.1 for expected velocity of the 100 grn , and 13- 13.4 for the 80 grn
This round should run with 257 stw so velocity in 3700 - 3800 + for 100 - 4000 for the 80 are conservative,
So I thought 1-11 should cover both bullets
25/26 nosler capacity is 93 grn

Looking forward to you thought's
The more info I get the better off I am !

Steve

 

[Shoebox]

Taj45
I used 100 nosler and 90 hpbt years ago with reasonable results both bullets would flatten pigs and goats
Then I met the ttsx great accuracy in 2506ai used both 100+80s settle for the 80s at 3800 + low recoil flat for what I want and still haven't recover a bullet
Stepping up to the 25 nosler won't do any harm I will settle for the most accurate, load development is going to be interesting
What are you using to spray copper with

Steve

 

[Berger.Fan222]

http://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi

I've found the JBM stability calculator to be very accurate. Here's the output for the 100 TTSX. Looks borderline, at least at sea level. But at higher elevations stability increases and the ambient pressure decreases. You would get a better estimate by plugging in your local pressure.

A 1 in 10" twist would be better for that bullet. Shot it for years in a 1 in 10" Sendero in 25-06.

The 80 grain TTSX will be full stable.

 

[jfseaman]

...PAC nor 4 grove 1- 11 twist...
Steve

If it's not too late, call Pac-Nor and get it changed to 9 or 10.

 

[jfseaman]

Reminder, I am a champion of the xx-Nosler designs. I have 27,28,30 and 33 variants.

A 257/26-Nosler may be reaching the point of diminishing returns.

No reason not to I just think you might actually go faster/efficient than the 25-06 with something else. Say a 257/270-WSM.

 

[Shoebox]

Berger.fan222
Thanks for putting in the effort !
I came up with the same number 3800 - 100 grn would be just inside exceptable spin rate, any thing over 3800 can only improve stability, I used both in my 2506ai, settle for the 80 grn accuracy was better, and didn't find anything the 100 did better (on longer shot maybe )
I'm a short ranger 400y for me is plenty!
I've recently turned 60 and decided to build a hot rod !
Even if I don't get "good " accuracy with the 100 grn chances are i will the 80grn
A bullet I know will do everything I want
With a few 100fps faster and that will make it "flat "
I must admit 80 grn ttsx in the 4000+ range sounds good !

Thank again thank !
Catch up again soon
Steve

 

[Shoebox]

Jfseaman
Thanks for the reply !!
I looked 25 wsm and thought it was to close to 2506ai, had a good look at the nosler case and thought, hello! giant 2506ai case! I believe its a good design,
As for diminished returns I thought about that, I have a friend over in western Australia who has 257 stw drive's 100ttsx in 3900+ and 80s 4200+
I don't know if I can equal or even come close, but I believe the nosler is a better design an will give it a run for its money
You being a xxnosler man might be able to throw some light on a question for me ?
The only case options I know of for 26 nosler are nosler + norma , for high pressure loads which case would you prefer, I am under the impression nosler brass is on the soft side,
Remember this is a unexplored wildcat
I have found zero info on it ,
Thanks again !
Steve

 

[Danny1788]

I thought, but not sure, that Norma makes Noslers brass. I built two 28 noslers and I'm testing 26nosler brass in mine and my buddy is testing 26nosler Norma Necked up. BOTH seem soft to me, even low and medium pressures we both are getting slight ejector marks but no case head expansion or hard bolt lift. Just seems like the brass is soft.

The 257STW will have almost the same case capacity as the 25nosler. You can start with low 257stw load info. I would watch for powder bridging and try powders like ramshot Magnum and US 869.

 

[Shoebox]

Danny1788
Hi
I seen photo's of bother types the nosler looked very yellowish - Norma looked ginger, I thought nosler made its own brass
Any colour difference that you noticed ?
Let me know how your test go !
Pitty Winchester doesn't make it
Thanks for the info
Steve

 

[Shoebox]

Danny1788
Powder selection in Australia is a bit limited, common powders ADI good range, Winchester n/a no slow
My gun shop can order in reloader but long lead time
Adi has some good slow powders and are temp insensitive, not that I would know I live in Queensland and It DONT get cold here !

Steve

 

[Rsadams]

If it's not too late, call Pac-Nor and get it changed to 9 or 10.

This... If theres a doubt and there's time , why not just change it..

 

[jfseaman]

Danny1788
Powder selection in Australia is a bit limited, common powders ADI good range, Winchester n/a no slow
My gun shop can order in reloader but long lead time
Adi has some good slow powders and are temp insensitive, not that I would know I live in Queensland and It DONT get cold here !

Steve

For the 80 grain TTSX, if you can get ADI AR 2218, stuff that 257/26-Nosler full and you should have an easy 3800fps.
For the 100 TTSX about %95 to %97 if 2218 will get you a good solid 3500fps.

Perhaps there is more speed than that. My QuickLoad reports slow numbers with very overbore setups.

 

[Shoebox]

Jfseaman
The numbers quick load shows might be a case of diminished returns, I was getting 3800+ with 62 grn ar2213 and the 80 grn in my 2506ai, but that was a warm load 70 thou off lands
That load worked in my rifle start low and work up, best group 4s
Thanks again
Steve

 

[Shoebox]

Rsadams
Ordered barrel through my gun shop smith 6-7 months believed lead time
So I've got a little time
Thanks for your reply
Steve.

 

[rifleman700]

Bryan Litz shows a 1-10" necessary for the 80 and 1-9" for the 115. Does not show 100.

 

[Shoebox]

Interesting view RL 26
This could get long winded !
What the heck we all deal with the wind !
Talking to a friend about loads for my build, he runs a 257 stw
I'm building a 25/26 nosler,
He also runs Barnes bullets, bullet discussion was lengthy
(still running Barnes 100's YES )
Powders he has used
Ar 2217
Ar 2225
Rl 25
Rl 26 gets 100+ fps and the accuracy is good ! Fed 215 m primers
I asked his thoughts on the burn rates ?
He believes 26 is slightly slower than 25
This is how he explained it which I thought was interesting

Same gun same bullet
Rl 25 expansion rate. 800
Rl 26. expansion rate 790
Pressure curve
Rl 25 burn time = 1.20
Rl 26 burn time. =1.30
1.20 x 800 = 960 push ratio
1.30 x 790 = 1027 push ratio

Push ratio = velocity

The chemical they add doesn't slow the burn rate it allows for longer burn time at the same rate ,

This isn't exact just a example ,

I said how do you explain higher pressure with same weight charge

How many times have you seen, one person praise a powder, great accuracy, no pressure ,better velocity,
Load xxx
Next guy runs out same load
Blows primer and can't get accuracies worth a shit,
So to many variables, the powder companies test that, if they recommend a burn rate you can bet its within x℅

This is bits of our texts, this is not scientific data just a friends
Explanation !

Hope you found that interesting
I did but then again I'm am old ,
Steve

 

[Gary in MD]

I don't know how many rpms that they are turning, I haven't even run them over the chrono yet but those 100 grain ttsx bullets out of my 10 twist 257 Wby kill the hell out of deer!! Plenty accurate too. I usually use RL22 but have also used 4350.

Gary