I picked up a # of Ramshot Tac. Ive been researching loads and found this.
TAC 80 SIE HPBT 21.9 2,500 24.3 2,749 54,308 2.260
Is it possible to load 80gr amax to magazine length in a ar?
ziton

It is unorthodox, but I have seen it done and by some of our club top junior shooters. These kids shoot at high levels in Service Rifle.

I had been skeptical but before they had to go off to college, they were using this technique across the course.

The typical 600 yard ammo is slow fire and single feed, so it doesn't have to be mag length. Generally the 77 SMK is the practical limit, but like I said, these guys were thinking out of the box and sunk those 80's in deep and just ran them. Now I don't hear any more about it. They are off at school and competing for slots at international levels and Olympic seats.

A typical RL-15 charge for 600 under an 80 SMK wouldn't fit if the bullet is sunk that deep. Those loads they used were in so deep the case mouth was unsupported.

The 77 SMK and the new Tipped ones are good to go at mag length for the 200 and 300 yard lines, and some are forced to use them at 600 just becasue they don't have hand loaded 80's. An 80 will shoot inside a 77 at the 600 when there is much wind to speak of.

Not sure about the Amax as noted the bullet shape is not ideal. You could try the Barnes bullets to load heavier than 77 to mag length. https://www.ar15.com/forums/t_3_16/671467__ARCHIVED_THREAD____Barnes_Precision_Match_5_56_X_45MM_85_grain_OTM_BT____Chronograph__Velocities_added__19_Apr_2015.html&page=2

a long time ago I saw someone posting photos and some information about 75gr AMAX loaded to mag length.  IIRC, it was on this forum. Memories are funny and faulty things, maybe someone can chime in and confirm my recollections.

As far as the TAC is concerned, It works well with the Nosler 80 gr CC. 23.5 gr with a Rem 71/2 primer and LC  brass is ~0.7" for the 8 5 shot groups fire so far. Got that load from

http://www.radomski.us/njhp/cart_tech.htm

Work up carefully. I would call 23.5 max in my rifles. I have gone up to 24 and backed off.



Last 5 5 shot groups

Is it possible?..... Yes.

Is it wise or productive?..........No.

Both the 75 and 80 AMAX's were designed to be single fed and too long for the magazine.........


Why are you thinking of doing this?

Just get appropriate bullets for the magazine.................. ?

ie the 77's posters have mentioned...........