6.8 spc or .300 ham'r?

[someguy2800]

I've got a 7mm tcu barrel if you're interested. .

nope, I’ve had one of those before though

yes that is a good platform for the ham'r and a good use for it plus you will not be blasting that ammo with a semi auto

I think it will be a good fit for it. A contender has about the same bolt thrust limit as an AR, so just like with an AR if you increase the bolt face size you have to reduce pressure. A 223 bolt face will allow for a full 60,000 psi pressure. I noticed looking at the specs for 300 ham’r that the case length is the same as a 357 maximum, and the base diameter of 223 and 357 are also the same, so MGM is going to make me a custom chambered barrel for a rimmed 300 ham’r. It just takes a single pass through a 300 ham’r die to form 357 maximum brass into 300 ham’r and then trim like .020” off. I’m not wild about the 300 ham’r name so I asked them to mark it as 308 maximum instead.

 

[robin banks]

nope, I’ve had one of those before though



I think it will be a good fit for it. A contender has about the same bolt thrust limit as an AR, so just like with an AR if you increase the bolt face size you have to reduce pressure. A 223 bolt face will allow for a full 60,000 psi pressure. I noticed looking at the specs for 300 ham’r that the case length is the same as a 357 maximum, and the base diameter of 223 and 357 are also the same, so MGM is going to make me a custom chambered barrel for a rimmed 300 ham’r. It just takes a single pass through a 300 ham’r die to form 357 maximum brass into 300 ham’r and then trim like .020” off. I’m not wild about the 300 ham’r name so I asked them to mark it as 308 maximum instead.

that is a great idea and now you have a round that you came up with

 

[greyling22]

so MGM is going to make me a custom chambered barrel for a rimmed 300 ham’r. It just takes a single pass through a 300 ham’r die to form 357 maximum brass into 300 ham’r and then trim like .020” off. I’m not wild about the 300 ham’r name so I asked them to mark it as 308 maximum instead.

Is that much different than a 30 herrett? (Side note, I actually am using a slightly shortened lee case length gauge for a 30 herrett to trim my 300 hamr brass)

 

[someguy2800]

Is that much different than a 30 herrett? (Side note, I actually am using a slightly shortened lee case length gauge for a 30 herrett to trim my 300 hamr brass)

i also have a 30 Herrett. The idea with this is to try to replicate 30 Harrett performance or close to it, but with a smaller stronger case. 30 Herrett is a bit more work to make because you have to cut the cases before forming, and I don’t get very good case life because the 30-30 brass has a very thin web. I tend to start getting case head separations after like 5 loadings even headspacing off the shoulder and shooting relatively mild loads.

30 Herrett on left, my 308 Maximum (rimmed 300 ham’r) middle, and 300 blackout on right



I had the same experience already switching from a 357 Herrett to a 357 maximum. Even though the Herrett is a much larger case I can actually push the 357 maximum about 100-200 fps faster with the same bullet because if I pushed the gas pedal just a little to far on the Herrett, the cases wouldn’t survive the natural springiness of a contender frame. I ruined a good bit of brass trying to get it to live up to its potential.

 

[MISportsman]

I did decide fully on the 6.8. I am putting the build together now. I went with a bison armory 16" barrel, stag upper lower and bcg, aero precision gas system and small parts, and Magpul furniture. I can't wait to try it out! Hopefully put some venison in the freezer this fall with it.

 

[Bcwitt]

Most .277 bullets are intended for 270 Win velocities. Not sure they would have the same terminal effect. There are lots of .308 cal. Bullets designed for intermediate velocities. Id say Ham'r.

 

[MISportsman]

Most .277 bullets are intended for 270 Win velocities. Not sure they would have the same terminal effect. There are lots of .308 cal. Bullets designed for intermediate velocities. Id say Ham'r.

I bought a couple of boxes of the s&b 110 gr pts to try out this fall. I've heard good things about them. I'll see how they do against a Michigan whitetail.

 

[Bcwitt]

I bought a couple of boxes of the s&b 110 gr pts to try out this fall. I've heard good things about them. I'll see how they do against a Michigan whitetail.

I hope it works out.

 

[BreechFace]

Most .277 bullets are intended for 270 Win velocities. Not sure they would have the same terminal effect. There are lots of .308 cal. Bullets designed for intermediate velocities. Id say Ham'r.

There’s several great .277 options for bullets designed for 6.8 SPC velocities.

90gr Speer Gold Dots
95gr Barnes TTSX
110gr Hornady Vmax
110gr Nosler Accubond
115gr Fed Fusion bullets
120gr Hornady SST
…and several more.

The 6.8 SPC was a very popular AR cartridge but many are just now finding it, quite a few great loadings were developed as it was in the running for military use so there was some heightened emphasis out towards it by ammo manufacturers. Not to mention it’s use for pigs and medium sized game.

 

[mongoslow]

145 gr fmj, 150 gr Deer season XP, 170 gr interlock....legendary

 

[amprecon]

Harrison sure has his fans, but I'm not one of them. I've tried 3 different ARP barrel's, and they were all utility grade at best. I've tried his 223, 6.5x6.8, and 6.8 SPC II barrel's and none of them would shoot consistent groups.

If you want a good 6.8 barrel, I'd suggest buying one from White Oak Armory. They will embarrass anything that Harrison sells!

I have two 16" ARP 6.8spcII scout profile 5R 1:11.25 twist barrels and they have been completely consistent for me with amazing accuracy.

 

[mshootnit]

I did decide fully on the 6.8. I am putting the build together now. I went with a bison armory 16" barrel, stag upper lower and bcg, aero precision gas system and small parts, and Magpul furniture. I can't wait to try it out! Hopefully put some venison in the freezer this fall with it.

That sounds sweet. My 6.8 build was a 18" Bison stainless lightweight barrel, Young chrome carrier, standard bolt, Aero upper reciever, POF straight trigger. Very nice rifle. I am sure you will like yours. I just busted 2 liter bottles at 200 yds with mine, no critters. The Hornady Black 110 Vmax was a very nice load in mine.