270 WSM fast twist build

[Lou270]

Berger .277 170s up on midway. You 7mm/6.5 mm fan boys need to come to the dark side, buy a bunch and build a nice fast twist 270

Lou

 

[khuber84]

Nope. The 277 175 tgk .56 BC is listed at 1900 fps. The 165 284 higher BC is .6something > 2600 fps and .510 and below 2600. So not higher based on that as not apples. The 277 155 lrx has a higher bc than the 7mm 168 lrx (.54 vs .51). The 160 lrx is new bullet optimized for very long head height of 7mm prc and has higher BC, but Will not work in a lot of saami chambers for other rounds. As for The 165 vs 168 ablr, Nosler revised their BCs and had Doppler testing done at Energetic Materials Research and Testing Center (EMRTC) at the New Mexico Institute of Mining and Technology. Any case My AB book does not have the 165 .277 ablr in it? Which version do you have? AB also shows the 180 eldm bc as ~.7 vs magical .8 that Hornady publishes The 170 Berger EOL is higher BC than 7mm hunting vlds lighter than 180 gr. So like I said there are no surprises

Lou

The 175 tgk is listed at 0.304g7 by ab. That's beaten by several 6mm, almost every 140+ 6.5 and virtually all sleek 7mm above 162gr. The 175 has a ton of bearing, very thick controlled expansion jacket

That is not true at all. The 175 tgk expands very well. I have blown multiple coyotes in half with it. The hollow point is very large on this bullet. It does have a thick shank so stays together and penetrates well despite the violent initial expansion. It is quite a good all around hunting bullet if you understand more about bullets than picking which has the highest BC

Lou

I've used the 140 tgk a fair bit in a prc/Saum, put it on the shoulder or they didn't expand much in my use experience, killed 4 animals with em 3 years back, I went back to 140hyb. All shots were shoulder, full pass throughs, shoulder bones, small holes though vitals, nick size exits. Also used the 100gr tgk from a 6cm on a doe kill hunt. Lots of runners on good shots, required 2nd round to dispatch.

I will not used a tgk, the heaviest for cal tmk is a far superior bullet. Keep using them if they work for you, but they didn't do well for me.

 

[Lou270]

305 seems about right. Where are you getting this from AB, by the way? I have the latest book but not the app? That would be more similar to the .617 g1 Browninglists in their box. I have only used the 175tgk and like I said, it blew coyotes in half to the point I was suspect of it. I then shot a couple very large boar hogs and blew through both shoulders and exited with good wide wounds. Several smaller pigs got bowled over but didnt pay much attention to terminals. According to press, The 175 was designed to be the heaviest bullet that Winchester could get in a short action with BC above .6. This is in ballpark with 6.5 hunting bullets in the 140-145 range. So, The 175 was not designed as the highest BC bullet possible. It was designed to work in a short action cartridge (same as the barnes lrx 155). The BC could be a lot higher (prob .75-.8) but then you would need more head height and a long action as the bullet would be a lot longer. There is a reason the 7prc is long action for ex.

Lou

 

[khuber84]

305 seems about right. Where are you getting this from AB, by the way? I have the latest book but not the app? That would be more similar to the .617 g1 Browninglists in their box. I have only used the 175tgk and like I said, it blew coyotes in half to the point I was suspect of it. I then shot a couple very large boar hogs and blew through both shoulders and exited with good wide wounds. Several smaller pigs got bowled over but didnt pay much attention to terminals. According to press, The 175 was designed to be the heaviest bullet that Winchester could get in a short action with BC above .6. This is in ballpark with 6.5 hunting bullets in the 140-145 range. So, The 175 was not designed as the highest BC bullet possible. It was designed to work in a short action cartridge (same as the barnes lrx 155). The BC could be a lot higher (prob .75-.8) but then you would need more head height and a long action as the bullet would be a lot longer. There is a reason the 7prc is long action for ex.

Lou

304g7, 594 g1 listed in the AB app for the 175tgk.

 

[Lou270]

Thank! Guess I will have to get the app if want latest info

Lou

 

[Raghornklr]

The browning 175 TGK are supposedly a different profile than the green tipped ones.

 

[wind gypsy]

Nope. The 277 175 tgk .56 BC is listed at 1900 fps. The 165 284 higher BC is .6something > 2600 fps and .510 and below 2600. So not higher based on that as not apples.

Ahh, good clarification. Sierra actually lists it as 0.560 @ 1900 FPS and above but that is not consistent with how they list other bullets and frankly dumb on their part! ABM has 0.304 G7 and a 0.284 G7 for the 165 7mm game changer.

The 277 155 lrx has a higher bc than the 7mm 168 lrx (.54 vs .51). The 160 lrx is new bullet optimized for very long head height of 7mm prc and has higher BC, but Will not work in a lot of saami chambers for other rounds.

160 LRX needing a 8 twist in a 7mm is akin to a 277 bullet (the 155 LRX) needing an 8 twist .277 tube. I'd assume that there are many more 8 twist 7mm barrels out there than there are 8 twist 277s. I don't understand why the 160 LRX wouldn't work in any 7mm SAAMI chamber with enough twist for it. Factory mag length is likely a different story.

As for The 165 vs 168 ablr, Nosler revised their BCs and had Doppler testing done at Energetic Materials Research and Testing Center (EMRTC) at the New Mexico Institute of Mining and Technology. Any case My AB book does not have the 165 .277 ablr in it? Which version do you have?

I used the sig app that I use for AB solutions in my sig range finder. They update the bullet library frequently in the app.