COMPARING THE HOTROD SST's 6, 25, 6.5

[MudRunner2005]

The Grendel is extremely anemic with lighter bullets going heavier isn't going to make it better. The high BC might help get a bit but the Grendel is much better suited to dropping down to a .22 Grendel and using 80-90gr bullets. This is where it really starts to shine at long range.

As for the 25sst, very promising bullet. Hopefully Sierra can keep up with the demand Blackjack is fueling.

How is it anemic? It has nearly .308 Win ballistics out to 1000 yards, but in a small package that fits in the AR15. We already shoot 123-130 grain bullets in 6.5mm out of it with no problems, so why not neck it down, and go with a much higher BC 131 grain bullet?

Why would you drop it down to a .22? They basically did that already with the .224 Valkyrie... And despite all the internet hype, there have been several youtube guys testing it that say it absolutely sucks and that it does NOT live up to the hype.

 

[MudRunner2005]

This 2506 shooter would also like some high BC bullets.

Same bullets work in all .257 calibers. You just need a 1:7 twist barrel. Also, if you do, I recommend bumping up the performance to a .25-06 AI 40º.

 

[rustyshackleford]

How is it anemic? It has nearly .308 Win ballistics out to 1000 yards, but in a small package that fits in the AR15. We already shoot 123-130 grain bullets in 6.5mm out of it with no problems, so why not neck it down, and go with a much higher BC 131 grain bullet?

Why would you drop it down to a .22? They basically did that already with the .224 Valkyrie... And despite all the internet hype, there have been several youtube guys testing it that say it absolutely sucks and that it does NOT live up to the hype.

If you did neck it down further and go heavier you'd have the same force acting over a smaller area + a heavier projectile. Just like the velocity of a 175 gr from 7mm-08 is slower than a 308 from equivalent barrel lengths.
I have wondered why they didn't neck 6.8 spc to 6mm though and run some 90-100gr though

 

[WiscGunner]

How is it anemic? It has nearly .308 Win ballistics out to 1000 yards, but in a small package that fits in the AR15. We already shoot 123-130 grain bullets in 6.5mm out of it with no problems, so why not neck it down, and go with a much higher BC 131 grain bullet?

Why would you drop it down to a .22? They basically did that already with the .224 Valkyrie... And despite all the internet hype, there have been several youtube guys testing it that say it absolutely sucks and that it does NOT live up to the hype.

The Grendel is only pushing a 123gr bullet about 2300fps in an AR and roughly 2600fps in a 24-26" boltgun. They do not stand a chance at matches beyond 600 yards so i put the cartridge into the "cute" short range plinking cartridge category. Essentially worthless in a boltgun as there are infinite other options with better performance that don't need any effort. Maybe if you hotrod the case and load it hot and run a long barrel you might get it to 1000yards. I have seen people show up to our local matches with them and they behave like shotguns at that distance because they are long past transonic. Heck even if you get the 131 ACE to run the same speed as the 123 ELDM it still falls apart at 700yrds. Even with that BC it only has 300yrds-ish before it bottoms out at 1000ft/lbs for hunting purposes. The cartridge has such little power it needs too light of a bullet to get any velocity (weak by today's standards) that you are forced to run lower BC bullets.

I suppose if that works for you, more power to you. I would love to hear success stories for that little cutie where people were able to get average performance out of it.

The .224 Valkerie and 22 Grendel are of similar performance with a slight edge to the Grendel. Factory ammo gives the advantage to the Valkerie. Feel free to run the numbers yourself but for long range the Valkerie is essentially a .223 improved.
Easy comparison is Hornady .223 running 75gr BTHP Match Bullets @ 2790 (transonic @ 883yrds). Same bullet in .224 Valkerie is running 3000fps (transonic 965yrds). The Valkerie pushing the 88gr ELD at only 2675fps goes trasonic @ 1056yrds. So a .22 Grendel has much further distance capability over a 6.5 Grendel.

This is why the 131ACE is so attractive as not only does it fill a void for those with 1/4bores with enough twist but also follows the competition trend to fo smaller diameter but heavier to drive BC up resulting in lighter recoil and better wind resistance. Now if Rich would do a Sherman-ized .22 to maximize some of these super heavy .22's that would be awesome! 80-90grs are the present but I would not be surprised to see 100+ gr .224 bullets in the near future in the effort to push BC's higher.

 

[Tidus56]

I look forward to the data on the 7sst.

 

[elkaholic]

I look forward to the data on the 7sst.

We should have some actual data by spring but I can tell you without doubt, after designing and shooting all the others, that it will run a 180 at 2900+ in a 2.9" magbox

 

[WiscGunner]

If you did neck it down further and go heavier you'd have the same force acting over a smaller area + a heavier projectile. Just like the velocity of a 175 gr from 7mm-08 is slower than a 308 from equivalent barrel lengths.
I have wondered why they didn't neck 6.8 spc to 6mm though and run some 90-100gr though

I would imagine that has a bit to do with the 175 .284 bullet being longer than the 175 .308 bullet and intruding into the powder capacity. This is the whole point of the Sherman Short Magnum cartridges...reducing this intrusion into powder capacity so the higher BC bullets can be seated properly when run at true short action length.

I didn't look hard but for a comparison here are 150gr bullets from Hornady in the .308 and 7mm. Obviously the 175gr bullets would seat even deeper into the powder capacity of the 7-08 while the 308 with 150gr has a bit a spare room yet to give to bullet space.

7-08 with 150gr ELD-X

308 with 150gr SST

 

[Bravo 4]

I would imagine that has a bit to do with the 175 .284 bullet being longer than the 175 .308 bullet and intruding into the powder capacity. This is the whole point of the Sherman Short Magnum cartridges...reducing this intrusion into powder capacity so the higher BC bullets can be seated properly when run at true short action length.

I didn't look hard but for a comparison here are 150gr bullets from Hornady in the .308 and 7mm. Obviously the 175gr bullets would seat even deeper into the powder capacity of the 7-08 while the 308 with 150gr has a bit a spare room yet to give to bullet space.

7-08 with 150gr ELD-X
View attachment 116328

308 with 150gr SST
View attachment 116329

Imagine how much powder space the bullet would encroach on if those were actually pictures of a 7-08 and .308...look a little long.

 

[rustyshackleford]

I would imagine that has a bit to do with the 175 .284 bullet being longer than the 175 .308 bullet and intruding into the powder capacity. This is the whole point of the Sherman Short Magnum cartridges...reducing this intrusion into powder capacity so the higher BC bullets can be seated properly when run at true short action length.

I didn't look hard but for a comparison here are 150gr bullets from Hornady in the .308 and 7mm. Obviously the 175gr bullets would seat even deeper into the powder capacity of the 7-08 while the 308 with 150gr has a bit a spare room yet to give to bullet space.

7-08 with 150gr ELD-X
View attachment 116328

308 with 150gr SST
View attachment 116329

It's both loss of powder capacity from encroachment and also a smaller area for the force to act on. That's why overbore cartridges benefit so much more from longer barrels. The more overbore and the longer the powder column the more suited to a longer barrel.

 

[Predator 22]

Imagine how much powder space the bullet would encroach on if those were actually pictures of a 7-08 and .308...look a little long.

The picture of the "7mm-08" has a belt!

 

[Cbass1019]

Imagine how much powder space the bullet would encroach on if those were actually pictures of a 7-08 and .308...look a little long.

Yea didnt realize 7-08s had belts ; )

 

[elkaholic]

Looks like we need a new thread maybe

 

[Predator 22]

Sorry Rich, wasn't trying to derail. Just having a laugh at that belted "7mm-08"!

 

[dirtytough]

We should have some actual data by spring but I can tell you without doubt, after designing and shooting all the others, that it will run a 180 at 2900+ in a 2.9" magbox

What's the difference in capacity between the 7ss and 7sst? They must be fairly close? I'm leaning on my 7ss pretty hard to get 3k with 180's from a 26" Bart 8 twist.