[Swamprabbit]

Anyone care to share what load has worked for you with the 80 grain Sierra matchking in a 20" barrel AR with 1:8 twist?

[Steve Smith]

Sure! First, do you have a chamber built for 80s? they should have a long throat, not a common throat.

[Swamprabbit]

Steve, I don't have the exact measurement here with me now but it is longer than what would fit in the magazine. I first thought this was strange for a match rifle but it appears this is the case so as to load the heavier bullets for single shot firing stages.

[Steve Smith]

Correct. The best way to do this is buy a Stoney Point OAL gauge, the .223 case, and a comparator. Then use an 80 (or several) to find your true OAL based on the ogive. Knock .010" off that measurement and load your 80 to that. Oughtta look awful long (there is a pic here somewhere of one of mine...oughtta look like that. Use the search feature.)

I use 24.3 grains of RL15, a Rem 7 1/2 primer, and an LC case. Shoots Xs at 600 regular like. Back that off to about 23.7 and wwork up slowly and carefully. It is a pretty warm load.

[Steve Smith]

Umm, did that help?

[Edward429451]

I wrote it down.:D

Lacking a Stoney Point Gauge, if you slightly crimp neck of empty case and seat a bullet in it long ang chamber it (or 5) and extract & measure them, subtract .010 like you said. Wouldn't that do the same thing for you, Steve?

The 80's probably have about a two caliber ojive, huh? long. Wonder what my 1/7" mini would do with them? (or would that be a waste of bullet?)

[Steve Smith]

Sorry, just got back to this. Wonderin if I helped Swamprabbit at all.

Well, you can try that if you want, Ed, but knowing my luck the measurememnts would be changed upon estraction. You will essentialy jam the bullet into the rifling so when you extract it, the rifling could have a tendency to "pull" the bullet, thereby skewing your results. Best to have the tool and just find where it touches, I think.

[Edward429451]

Yeah, its on the list, along with a new chrony, scope, ammo. It never ends. Santy Claus is comin, wonder if he knows I could use one? I better make sure at least the elf knows.:D

[Steve Smith]

Hint-take the bullet you use and store it with your gauge. That way you can keep track of throat erosion. Different bullets would give different measurements.

[Edward429451]

Good idea!;)

Have you found same bullet / different lot to have differences in ojive? I swage a little and save bullets to reset the dies for various bullets, and I see that minor differences do occur for me lot to lot. Not huge differences, but discernable by eye.

[Steve Smith]

You'd think that match bullets would have closer tolerances, but no, you'll find some short ogives every once in a while. Best to find one that's the "average" and stick with it.

[Edward429451]

Duh:D

Thanks Steve.

[Dave P]

Well, in my new RR servicerifle (1/8) with new nosler 80 grain bullets, I loaded up some 4064. Got excellent results at 600 yrds, with about 15 mph wind!

Check the books, but I was around 21 + grains (I think).