6mm Wildcat 3800fps

[wilkup]

I'm looking for a 6mm that will push the 105gr VLD over 3800fps and fit into a true short action (2.95'').
I'm thinking of using a 7mm WSM case as the parent and making some improvements from there.
If anyone's done this already, I'd love to save the time and money and just get their reamer instead.

 

[IdahoCTD]

I have a 6wsm. It won't make that speed. It topped out around 3600fps with a 28" barrel. You would have to go to a .378 Weatherby/338 Lapua case head. The only brass I know of for a short action like that is Lazzeroni unless you want to form it from 300 Norma stuff. There was a article years ago about a 6 MachIV which was a 7 mag case necked down and improved that was in the same 3600-3650fps range with 105's. That Mach IV case has more capacity then a WSM can ever hope for no matter how much you modify it.

 

[Rich Coyle]

I made a short 7mm on a .243 Rem 700 action. I shortened the .378 Wea to 2 1/4" with a 1/4" neck and 40 degree shoulder. It had the same volume as a .300 Weatherby. You should be able to get there if you do something like that. Of course you will be limited to the slowest powders.

 

[tbrice23]

I'm looking for a 6mm that will push the 105gr VLD over 3800fps and fit into a true short action (2.95'').
I'm thinking of using a 7mm WSM case as the parent and making some improvements from there.
If anyone's done this already, I'd love to save the time and money and just get their reamer instead.

6mm VLDs are not invincible.
Jacket failure is probable with the Hunting vld with aggressive twist and incredible velocities.
If my goal was 3800 fps with 105s I'd give the VLD targets a try.

But I definitely would be more likely to look at a solid or bonded bullet.

 

[tbrice23]

On a side note,
I ran into a guy that had a 6mm-338 Lapua wildcat. He said he was running 108 SMK at 4200fps. I definitely asked him how frequent was jacket failure. He said none because his barrel was a 10 twist. ( none that he knows of).
The less aggressive twist and the thicker jackets of the Sierra Match Kings let him get away with it.

I'm not sure how may critters that guy has shot and lost to this date because of "ice picking" effect. (Lack of terminal damage due to lack of expansion).

 

[IdahoCTD]

I shot Amax's in mine with a 8 twist and never had a problem. Typically new barrels are OK but once they get some wear the bullets really start to come apart. In heavy overbore calibers many times that is less than 200 rounds.

 

[Rich Coyle]

I shot Amax's in mine with a 8 twist and never had a problem. Typically new barrels are OK but once they get some wear the bullets really start to come apart. In heavy overbore calibers many times that is less than 200 rounds.

With this posted one should certainly consider salt bath nitride. One might get 400 rounds or more.

 

[Deleted member 46119]

Cartridge : 6-7 mm Winchester Short Magnum
Bullet : .243, 105, Berger Hybrid #24433
Useable Case Capaci: 76.289 grain H2O = 4.953 cm³
Cartridge O.A.L. L6: 2.950 inch = 74.93 mm
Barrel Length : 28.0 inch = 711.2 mm
Powder : Alliant Reloder-33

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.362% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-13.6 82 63.41 2955 2035 34360 13670 90.8 1.683
-12.3 83 64.41 3008 2110 36066 13969 91.8 1.654
-10.9 85 65.41 3062 2187 37865 14259 92.8 1.617
-09.5 86 66.41 3117 2265 39763 14540 93.7 1.580
-08.2 87 67.41 3171 2345 41765 14810 94.6 1.543
-06.8 89 68.41 3226 2426 43858 15068 95.4 1.508
-05.4 90 69.41 3280 2509 46044 15313 96.1 1.474
-04.1 91 70.41 3335 2593 48335 15546 96.8 1.440
-02.7 92 71.41 3390 2679 50742 15764 97.4 1.407
-01.4 94 72.41 3445 2767 53272 15967 98.0 1.375
+00.0 95 73.41 3499 2855 55930 16155 98.5 1.344 ! Near Maximum !
+01.4 96 74.41 3554 2945 58725 16326 98.9 1.313 ! Near Maximum !
+02.7 98 75.41 3609 3036 61665 16479 99.3 1.283 ! Near Maximum !
+04.1 99 76.41 3663 3128 64759 16616 99.6 1.254 !DANGEROUS LOAD-DO NOT USE!
+05.4 100 77.41 3717 3222 68017 16733 99.8 1.226 !DANGEROUS LOAD-DO NOT USE!
+06.8 101 78.41 3771 3316 71448 16831 99.9 1.198 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 95 73.41 3705 3200 69439 15766 100.0 1.221 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 95 73.41 3218 2415 43181 15408 91.0 1.505

 

[Deleted member 46119]

You will probably get there or close with the least hassle going down the necked down 7mm WSM route. example previous post.

If you get a "fast" barrel. No problem. If you get a "slow" barrel, very hard to get there.

I found out how much difference a barrel can make with my 277/26-Nosler vs my 284/26-Nosler (now officially 28-Nosler). Made ~4000 with the 277/26-Nosler and copper 115s

 

[TXAoudadKlr]

This thread has me curious on how well a 6.5 4s necked down to 6mm would perform.

 

[adam32]

This thread has me curious on how well a 6.5 4s necked down to 6mm would perform.

The same as a 6mm SAUM...which is about the same as a 6-350 Rem Mag...which is about the same as a 240 Weatherby...gun)

 

[Deleted member 46119]

The same as a 6mm SAUM...which is about the same as a 6-350 Rem Mag...which is about the same as a 240 Weatherby...gun)

There are lots of cartridges that can be necked down to 6mm. Consider the hole and the pressure has to pass through it. There is only so much time in the barrel.

 

[TXAoudadKlr]

The same as a 6mm SAUM...which is about the same as a 6-350 Rem Mag...which is about the same as a 240 Weatherby...gun)

Touchè. gun)

 

[IdahoCTD]

R-33 isn't going to give the best velocity when it's that overbore. R-50, 869, WC872, etc are going to be your friends. But like I said....around 3600fps is a safe max. Sure there are fast barrels that get 150fps more on occasion but it's not the norm.