223 freebore with 80smk and 75 AMAX

[chuckbuster243]

What freebore is working best with the 80 SMK and the 75 AMAX? I have two reamer options one is a wylde with a .2558 neck and .0619 freebore and a 223 match @ .254 neck and .090 freebore. Up to hear your opinion. I do have a 22 throating reamer and can lengthen the throat if needed but would rather not if I can get it to work as is. Also what lead angle 1.5 degree or 1 degree 15 min. Thanks Matt

 

[areaone]

Wylde

 

[ronemus]

I prefer the longer throat - more room for powder. As it is I use mildly compressed loads of N550.

 

[chuckbuster243]

How much freebore to get boattail over neck shoulder junction? I like the idea of more powder just dont want a mile long throat. Thanks Matt

 

[Phil]

IF i remember correctly, i was told that a .077" would be good for the 75 Amax bullet.....

However, i don`t know how deep it would be seated as i went a different direction.

That holding true you might be better going shorter, it`s always easier to make it longer.

Phil.

 

[fdshuster]

I don't know about the 75 gr. A-Max, never use them, but when I spec'd my 223 Rem. PTG reamer a number of years ago, I went with a .072" freebore. It has cut 5 or 6 chambers, for my son and myself, and for us, the .072 freebore has worked perfectly. 80 gr. SMK's can be seated to touch the lands, and the full diameter base of the 80 gr. will be in front of the donut. Bullets as light as the 55 V-Max can still be seated to touch, with their bases about 1/2 of the way up the case neck. Still plenty of bullet to case neck contact.

Leade angle is 1.5 degrees. Equally important is the chamber neck diameter of .253" for a Lapua no-turn loaded diameter of .250". Brass is being worked from a maximum to .253" to the minimum bushing diameter of .248", and never is thrown out because of case neck splits. Have never annealed.

 

[jsthntn247]

.110 of freebore puts a 80 berger above the neck shoulder junction by about .020

 

[chuckbuster243]

The throater I have is a 1.5 degree. If I get a shorter throat chamber but it has a 1.25 degree throat angle. If I lengthen it I should then have a full 1.5 degree then right? Since it will have cut the shallower angle out first and then cut the longer length vs going the other way?

 

[chuckbuster243]

Anybody have the bearing surface measurements on the 75 amax and 80 smk?

 

[6xcshooter]

what kind of magazine to use? i'm sure they wont fit in most conventional magazines unless you seat really far in. could you use a different box in a 700 remington?

 

[ronemus]

For mag length loads use the Hornady 75 gr BTHP; the BC isn't as high as the A-Max, but it's higher than anything else you can readily use from a magazine. Several years ago you could buy "VLD mags" from DPMS (since discontinued) - they allow a COAL of ~2.55" by putting the case heads in the rib and using a straight stack instead of staggered. That reduced capacity to 10 rounds but alowed long bullets to be seated above the neck-shoulder junction. They weren't very popular because a modified bolt catch incompatible with standard mags was required, and of course the reduced capacity. I have a set that I run in my rifle for NRA Highpower competition (8-round max per the rules) and run 75 gr BTHPs seated well out so I can use plenty of N-550 without compressing the load. That lets me run an easy 2930 fps from a 28" barrel, and the high BC bullets do well in the wind. I could run A-Maxes from the magazine, but the advantage is so small at 200 - 300 yards that I don't bother.

 

[chuckbuster243]

These will be shot single shot from a boltgun.