I'll get this added to my other bullet testing thread soon, but I thought I'd start a separate thread as well since I'll be doing more than just the gel tests with this bullet.
I picked up a box of these to test out in a large (110gr case capacity) 270 wildcat. I have two barrels, one is a 28" Broughton 8.5" twist and the other is a 25" K&P 7" twist (depending on who you ask.....). For anyone who hasn't had one of these bullets in their hands, they're ridiculously long with a bearing surface a mile long! LOL
That's a 140 TGK, 170 Berger, and 175 TGK.
The long bearing surface and my relatively short freebore made me stay pretty conservative with my starting loads. I backed down my loads for the 170 Berger with US869 and worked up from there. To be honest, my 170 Berger loads are pretty mild too just because that bullet shot terrible (3 MOA) over 3100 fps. The charges I loaded up only brought me to 3045fps from the 28" barrel, with no pressure signs and the primer edges looking nice and round still. I can definitely run the charges up higher. I imagine I can land in the 3250-3300 range without any issues.
I was really interested to see how the bullet was going to perform from the 8.5" twist barrel since Sierra recommends an 8" twist. All of the shots (7 total) I fired while checking powder charges went into a 1.5" group at 200 yards with nice round holes. I saved one round at the top charge I had loaded (3045fps muzzle velocity) to shoot into the gel blocks. This is what I ended up with:
The velocity written on the block is the approximate impact velocity. Everything looks pretty good from this angle. The top down view is a little different though.
The bullet cut hard left and exited the second gel block after 19" of total penetration.
This performance circles back to a question floating around about bullet penetration with marginal stability. The bullet appears to be shooting well, it showed great expansion at this impact velocity, but as soon as it started to expand, things literally went sideways. This is very different from the two other Sierra TGK bullets I've tested so far which were the 140gr .277 (8.5" twist barrel) bullet and the 165gr 7mm (9" twist barrel) which both penetrated in a perfectly straight line and were both recovered in the gel.
The next trip out with this bullet will be with the 25" long 7" twist barrel. I'll load up some heavier charges to see how the velocity looks and then send another bullet into the gel. I'm anxious to see if there's a change in the penetration.
If anyone else has played around with the 175 TGK in any other 270s, please post up your results so we can get a little more data going. I have high hopes for this bullet as long range plinking bullet for this gun since the 170gr Berger just shoots scatter plots no matter what I do! LOL
I picked up a box of these to test out in a large (110gr case capacity) 270 wildcat. I have two barrels, one is a 28" Broughton 8.5" twist and the other is a 25" K&P 7" twist (depending on who you ask.....). For anyone who hasn't had one of these bullets in their hands, they're ridiculously long with a bearing surface a mile long! LOL
That's a 140 TGK, 170 Berger, and 175 TGK.
The long bearing surface and my relatively short freebore made me stay pretty conservative with my starting loads. I backed down my loads for the 170 Berger with US869 and worked up from there. To be honest, my 170 Berger loads are pretty mild too just because that bullet shot terrible (3 MOA) over 3100 fps. The charges I loaded up only brought me to 3045fps from the 28" barrel, with no pressure signs and the primer edges looking nice and round still. I can definitely run the charges up higher. I imagine I can land in the 3250-3300 range without any issues.
I was really interested to see how the bullet was going to perform from the 8.5" twist barrel since Sierra recommends an 8" twist. All of the shots (7 total) I fired while checking powder charges went into a 1.5" group at 200 yards with nice round holes. I saved one round at the top charge I had loaded (3045fps muzzle velocity) to shoot into the gel blocks. This is what I ended up with:
The velocity written on the block is the approximate impact velocity. Everything looks pretty good from this angle. The top down view is a little different though.
The bullet cut hard left and exited the second gel block after 19" of total penetration.
This performance circles back to a question floating around about bullet penetration with marginal stability. The bullet appears to be shooting well, it showed great expansion at this impact velocity, but as soon as it started to expand, things literally went sideways. This is very different from the two other Sierra TGK bullets I've tested so far which were the 140gr .277 (8.5" twist barrel) bullet and the 165gr 7mm (9" twist barrel) which both penetrated in a perfectly straight line and were both recovered in the gel.
The next trip out with this bullet will be with the 25" long 7" twist barrel. I'll load up some heavier charges to see how the velocity looks and then send another bullet into the gel. I'm anxious to see if there's a change in the penetration.
If anyone else has played around with the 175 TGK in any other 270s, please post up your results so we can get a little more data going. I have high hopes for this bullet as long range plinking bullet for this gun since the 170gr Berger just shoots scatter plots no matter what I do! LOL
