6.5-270 (257) Wby Mag...What do I need?

[highdrum]

@Longtooth32 what did you change in your rifle to get a longer magazine box to fit up to 3.7 coal? Thanks......

 

[Longtooth32]

@Longtooth32 what did you change in your rifle to get a longer magazine box to fit up to 3.7 coal? Thanks......

Shooting an ARC Mausingfield action with Savage pre-fit barrels. Max COAL on a Mark V 270 Wby action is 3.4"

 

[Longtooth32]

Just found this if View attachment 100642

Anyone is interested .

Yah...I found that after I bought 7mm Wby bushing dies and a 6.5mm stem...

6.5/257 Wby barrel should be here tomorrow...

Now I am thinking about a .257 Wby in a fast twist now that the quarterbore heavies will be coming out...do not feel like dealing with finding throated reamers in 25-284...unless Blackjack...

 

[Longtooth32]

Well, I put her together today...

The Pac-Nor barrel as above.
Pic of the 150s for tomorrow...

I fully expect to get to well over 3300fps with the 150s in my 28" barrel...

I think that the 264 Win will be in my rear view mirror....

 

[Longtooth32]

Well got out and shot some today...it was a good practice with dry firing with live ammo in the chamber...

Anyways...known problem with the Nucleus action with a light firing pin spring of 16 lbs...ARC sent me a 19 Lb spring for no charge...I am shooting "thick" Russian mag primers...

So...some primers ignited after 1 to 5 strikes...again good practice..

The 150gr Sierras @ 69gr of RL26 (my lowest starting load) with only 12 rounds down the unfired barrel ran @ 3240 fps with an ES of 20fps... 28" barrel

I am putting in the 19 lb spring tonight...

The last three rounds before dark, landed sub 1"...

 

[Longtooth32]

Put the 19Lb striker spring in today...

Finally got some data points and I have to pull about of 20 rounds of ammo because they would be way too hot.

I was not getting any of the usual pressure signs with this Nucleus action. Then it suddenly locked up with the next one grain increase in powder. I actually had to kick the action open with the rubber sole of my boot.

But holy cow the barrel was putting down some impressive speeds.

The rifle was shooting this target (yes, I biffed one) @ an average speed of 3427 fps with an ES of 27 from 10 rounds, and then it locked up with one more grain of powder from this load.

Again, bipod and rear bag out of the back of my pick-up. Lased 101 yards.

28" barrel, 1-8 twist, Magnetospeed on the end of the barrel...150 gr Sierra Match King. Necked down 270 Wby brass.

If I step down the powder by two grains from the above load I still get an ave speed of 3372fps with an ES of 8 for 5 rounds.

What kind of speeds can a reloaded 26 Nosler put down?

I have 6.5mm 160gr Matrix bullets inbound.

 

[Edd]

You're ok with loading 150 gr 264 bullets to speeds faster than Weatherby gets with 130 gr 277 bullets?

 

[Longtooth32]

You're ok with loading 150 gr 264 bullets to speeds faster than Weatherby gets with 130 gr 277 bullets?

My 270 Wby (28" barrel, 1-9 twist) is pushing 130 SSTs @ 3650 fps and 140 SSTs @ 3575 fps with out any load development...

Here is a pic of the group of the 140 SSTs...

 

[Longtooth32]

I just went to the Nosler 26 reloading data page...

They are burning over 85grs of powder to maybe get to 3250 fps on the 140s with a 26" barrel...

I am burning 71 to 73 grains of powder to push 150gr (not 140s) in a necked down 264 Roy (Wby)x 257 to 3375 to 3425 fps in a 28" barrel...

Wby in my opinion missed this cartridge when they went to 6.5 x 300 Wby instead of a necked down 270/257 Wby...

RL 26 maybe too fast/dense loading...next loading with H1000 to maybe get faster...

 

[D-mon]

Hi,
I have started a 6.5-7 mm weather project a bit more than a year ago.it has and still is a very big frustration for me.
I first talked to Dave Manson and got a reamer ground for shooting the 147 gr eldx.
Neck diameter is at .295 and free bore is at .180 .i specified that I would be cleaning up the neck of my cases by doing a light neck turn.loaded round is .290 of neck diameter .

I built the rifle with a second hand ex match barrel in 6.5x47 on a tikka t3 action, finishing at 26".i wanted to check speeds and loads before committing to buying a brand new barrel
Beware most of the following loads could potentially be too hot loads in your rifle and dangerous!!!
I started my load development with 120 a max, 130 a max and 147 eldm. Bullet were seated initially 1 mm of the land.
Powder was AR 2217(H1000).
The 120's load was from 67 to 72 grains.
The 130's load was from 65 to 69 grains.
The 147's load was from 64 to 67 grains .
When I tested those loads, the 120 would start to get high pressure at 69 grains, the 130 were high from the 65 grains load, the 147 grains were blowing primers at 64.

I got suggested to go with a slower powder so I then tried retumbo, with the 147, starting at 62 grains. Again first round blown up primer.
I tried rl33 with 59 grains behind the 147 grains, again blown up primer.

So today I went to the range again, I had loaded some 123 sst with retumbo going from 67 ,68 and 69 grains. Recording speeds were 3228-3292-3316 respectively. Primers were slightly flat but bolt was easy to lift up with no marking on the brass.i will pursue in that direction.
I had some 147 loaded at 59 grains with the bullet seated deaply so as to increase the distance of freebore to the rifling. And that one blew up a primer as well , speed was 3182.

It seems that using the 147 in that rifle is a disillusion .
Hornady published the following data for the 264 win mag with the 147:

https://press.hornady.com/assets/site/hornady/files/load-data/264-win-mag-140-147gr-data.pdf

I was trying to think what would cause so high pressure:
The barrel has a bit of fire cracking just after the throat, could that create too much friction and increase the peak pressure?( I have polished the beginning of the rifling with jo bore paste to try to smooth things out).
I have heard of batches of weatherby / Norma brass being too soft. Could that be the case with that batch?
I have dried out the inside of chamber of any oil and made sure that the brass was clean as well.

Is my neck clearance enough?
How fare from the rifling would you suggest that I seat my bullet to minimise pressure?
Is my throat too short?

For those on the forum who use the 147 in 6.5 Prc or other magnums ,do you guys have any issues with over pressure?
Is the long bearing surface of that bullet the issue?
that is a good lot of questions I have asked around but I haven't got a clear answer so fare.
If anybody here could help that would be great.
I am not that new to reloading, having played with more than a dozen calibers over the last years from 204 ruger to 505 Gibbs including 243,6.5 creedmoor, 308, 300 wm, 458 socom among others.
But it is the first time that I have so much trouble with one cartridge.

 

[Edd]

A 6.5 Creedmoor has .199" of freebore and the factory loaded 143 gr ELD-X bullets jump about .090" to the lands.

 

[Longtooth32]

I must of missed a time out limit...stuff was deleted...

Anyways...

Just got a boatload of Matrix 160 VLD hunters... .264"

Looking forward to shooting these over 3300 fps out of my 28", 1-8 barrel...

This chamber should have an about .357 freebore...

.332 G7...for the 160 Matrix... this will be fun...

 

[Mike D Texas]

Sorry for tagging a necro thread but i'm looking at this same build but using necked up 257 Wby brass.

 

[D-mon]

It should work fine. Just check the reamer neck diameter and the diameter of the final neck with the projectile you intend to use.