Black Hills 5.56 70 gr GMX

[Chuck Haggard]

Hence my original statement.

Have you ever actually shot an AR or any other rifle with different types of ammo? I don't mean to sound like an ass but it doesn't sound like you have.

Example; my Savage .308 deer gun shoots 150gr Federal SPs to the zero I have set for that ammo. I haven't seen that ammo on the shelves since before the giant ammo panic. I try Remington and Winchester 150gr SPs, the Winchester load shoots 2" low from my zero, the Remington shoots an inch high and three inches left.

My Colt that I use as my patrol rifle shoots M193, Hornady 60gr SPs, and M855 to POA=POI at the 100, even though they have different trajectories on paper. At distance they with obviously hit to different points of impact, but from 0-120 yards they hit to POA. Contrast this to the other M193 types that I have on hand from other countries, same ballistics on paper as the LC M193, but one of the samples I have on hand shoots several inches right and high off of my zero.

There is no chart in the world that will tell you how different ammo will shoot from your gun when shot by you.

[Unobtanium]

Have you ever actually shot an AR or any other rifle with different types of ammo? I don't mean to sound like an ass but it doesn't sound like you have.

Example; my Savage .308 deer gun shoots 150gr Federal SPs to the zero I have set for that ammo. I haven't seen that ammo on the shelves since before the giant ammo panic. I try Remington and Winchester 150gr SPs, the Winchester load shoots 2" low from my zero, the Remington shoots an inch high and three inches left.

My Colt that I use as my patrol rifle shoots M193, Hornady 60gr SPs, and M855 to POA=POI at the 100, even though they have different trajectories on paper. At distance they with obviously hit to different points of impact, but from 0-120 yards they hit to POA. Contrast this to the other M193 types that I have on hand from other countries, same ballistics on paper as the LC M193, but one of the samples I have on hand shoots several inches right and high off of my zero.

There is no chart in the world that will tell you how different ammo will shoot from your gun when shot by you.

A bullet's BC does not appreciably change from platform to platform (rifling could make a minute impact?)
Velocity is what it will be.

The 70gr GMX and the 77gr SMK have very similar BC's, and their muzzle velocities are also very similar, with the GMX being a touch faster out of the muzzle, and the SMK having a touch higher BC. They should track nearly identically. From the very onset of this thread, in my very first post, you will note that I discussed POI/POA variance from ammo to ammo. I have shot multiple loadings in multiple AR platform weapons and observed such, as my example in a previous post depicts. Respectfully, I don't think you're reading my posts.

Bottom line: Optics/holds for MK262 shouldn't change much, if at all, for 70gr GMX. Just change the zero. Just as I said initially. It's kindof nice to have a round that tracks with an existing round that is popular enough to have optics made specifically for it.

[Chuck Haggard]

However one can not just load up with any of the above, use the optics for holdover, and expect to hit what they are aiming at, without confirming on paper that this is the case.

Yes, the ballistics in a rifle zero'd for THAT loading will be to same as if it were shooting the other similar loads, but one can not typically switch between different rounds without having to rezero, unless one has already confirmed at the range that the two different loads shoot to the same zero.

I have had to rezero precision guns in the past when the exact same ammo from the exact same brand hit differently due to being from a different lot number.

[Unobtanium]

However one can not just load up with any of the above, use the optics for holdover, and expect to hit what they are aiming at, without confirming on paper that this is the case.
Correct.
Yes, the ballistics in a rifle zero'd for THAT loading will be to same as if it were shooting the other similar loads, but one can not typically switch between different rounds without having to rezero, unless one has already confirmed at the range that the two different loads shoot to the same zero.
Yep.

I have had to rezero precision guns in the past when the exact same ammo from the exact same brand hit differently due to being from a different lot number.

Look, buy a VCOG calibrated for MK262 and use it for 70gr GMX. Works damn good within a very VERY slight variance. That's all I've ever said.

[Rich]

The 70gr GMX is tracking with MK262, ballistically. Whether this matches POI/POA, I do not know, but holds and BDC's should be nearly interchangeable. Out to about 500 yards, M193 is within a coffee-can of MK262.

Black Hills says the "floor" for 70gr GMX is 2100fps.

My carbines are zero at 50y using MK262
M855 has almost the same POI as the MK262 out to 220y (no more than a inch)

The berm is around 220yrds ?

using ML2 4MOA DOT can hit clays on the berm with M193,M855,Mk262, BH blue 77 and 75gr and the BH 50gr TSX


One of these days I might fine tune the aimpoint for the 50gr TSX

[Rich]

Look, buy a VCOG calibrated for MK262 and use it for 70gr GMX. Works damn good within a very VERY slight variance. That's all I've ever said.

I wonder why they wont offer the Optimized BT

[witchking777]

For Doc,any tests done or planned in the future on this?

[Chuck Haggard]

Look, buy a VCOG calibrated for MK262 and use it for 70gr GMX. Works damn good within a very VERY slight variance. That's all I've ever said.

We agree on that.

[El Cid]

Any updates on this 70gr GMX load? Looking for a contact to 400 round I can standardize with. Was looking to use 70gr TSX but it's so tough to find.

[Unobtanium]

Any updates on this 70gr GMX load? Looking for a contact to 400 round I can standardize with. Was looking to use 70gr TSX but it's so tough to find.

Contact to 400 is a very tall order, and I doubt the 70gr TSX or GMX can deliver. The TMK can, though, if you are okay with giving up barrier performance. I have only seen the new 62gr waterproof stuff. Not the 70gr, yet. Black Hills is working on it.