Help with .308 Load SMK not expanding.

[Deviant]

I have a lightweight custom built AR-10 that I carry when hunting thick brush. I run it suppressed so I built it with a 16 inch barrel to keep it short. I have been shooting Federal gold medal match 168 grain Sierra match King ammo because it Shot well and I figured it was a cheap way to get brass because I got a heck of a deal on 400 rounds of it. I have shot quite a few deer with this gun walking through the woods and most of the **** things run off and then I have to spend 2 hours tracking them down. I get a pencil-sized entrance hole and the exit hole is about the size of a nickel. Shot placement has been pretty good usually lung shots but they still run off even when damaging both lungs. I have not ran this through the chronograph to see what my FPS is but I'm thinking I don't have the Velocity for the smk to expand efficiently. I am thinking of switching to the 110 grain or 125 grain GMX or other bullets if someone has a suggestion. I know my velocity will be limited due to the 16 inch barrel but I was wondering if anyone had any load data for the 110 or 125 out of the 16 inch barrel in an AR type rifle. Or any other suggestions to get better performance out of a different bullet. Any help or suggestions will be appreciated. Yes I could switch rifles I do have plenty of other rifles to choose from but most have long barrels or are not threaded for a suppressor. I have enough hearing loss as it is so I prefer to hunt with a suppressor to save what hearing I have left. And it would not be ideal to wear earplugs while walking through thick brush and stalking Critters in the woods.

Thanks, Al

 

[WeiserBucks]

SMK's are notorious for poor expansion. Try a different bullet .

 

[J E Custom]

When I shot the match kings I found that I had better results when I trimmed the Meplat. All you have to do is trim just enough to open the tip about 1/16 th to aid in the expansion.

The link will show how to do this and the tool shone can be used with the loaded rounds if set correctly using the bullet Ogive and holding the cartridge.

I also found this process very useful on led tipped bullets that were damaged from chambering many times.

J E CUSTOM

 

[yorke-1]

Just switch bullets for hunting. The SMK was never really designed to expand like a normal bullet and the low velocity isn't helping.

I'm sure you can find a more predictable hunting bullet that will shoot to a similar POI when loaded at similar velocities.

 

[alaska]

Sierra SMK is a match or sniper bullet not made for hunting.
For your short barrel suggest IMR 8208 and 130gr Barnes TTSX excellent deer bullet and light recoil.

 

[Deviant]

Thanks for the replies. I have some lehigh 110 grain controlled chaos and some ttsx to try. I also have 2 lbs of 8208 to try. I have used the 168 grain SMK for years in my Sako A7 and it has taken lots of deer but they are loaded a lot hotter than they are in my AR.

 

[alaska]

The Berger Classic Hunter 168gr
CFE 223 @ 46.0 will get back some Vel lost in the short barrel 308 Win (my load) And for me it shoots like SMK very accurate and deadly. TAC powder is another good powder for shorter barrels. If deer is on your menu TAC and 150 gr Nosler BT or Sierra Gameking would be good.

 

[J E Custom]

Thanks for the replies. I have some lehigh 110 grain controlled chaos and some ttsx to try. I also have 2 lbs of 8208 to try. I have used the 168 grain SMK for years in my Sako A7 and it has taken lots of deer but they are loaded a lot hotter than they are in my AR.

The reason I recommended trimming the meplat was because you said you had 400 loaded rounds and it would save you from pulling the bullets and re loading the cases.

Before all of the new bullets, lots of people found that the Match King was the most accurate bullet, but not the best performing hunting without doing something to it.

I haven't used them for hunting in years, but if I had to, I could by trimming the Meplat. it is just a way to use them if you want to. Once they are trimmed, they perform well especially at long distances.

Just a way to utilized what you have.

J E CUSTOM

 

[Capt RB]

I run 165 ballistic tips in an 18" 06 at about 2650. Your suppressor should put your velocity at about 2500 maybe 2550fps. Any of the bullets designed for the 30/30 will get it done. Also 125grn class of bullets would be well suited. The accubond due to the bonding would be a first choice for lead and the gmx barnes or hammers for green bullets. The hammers will be a fast load work up.
I'd try the meplat trimming on some coyotes to make sure I was getting the expansion at your velocity handicap before I'd continue with deer sized game.

 

[Bravo 4]

Your velocity isn't the problem, slipping through the woods shooting whitetail suggests you are fairly close. Do as JE suggested (bare minimum check the tips to make sure they aren't clogged) and they will at least be more consistent. I have put .308 Matchkings through several living creatures and they will kill, but aren't made for it or necessarily the "best" choice in my opinion. Haven't tried any of the tipped SMKs but from my experience the only Matchkings I will use for hunting is the 300 grain .338. They are devastating and consistent. Buddy uses the 250s and swears by them. Lots of guys use various SMK in a multitude of weights, calibers and chamberings successfully on game every year, I wish I trusted them as they are generally very accurate...you know, the whole shot placement trumps all else kinda thing. I'm sorry, I just want my cake and be able to eat it too! I'm selfish like that.

 

[Csafisher]

sierra MATCH king. Load up some accubonds when you get a chance.

 

[Deviant]

The reason I recommended trimming the meplat was because you said you had 400 loaded rounds and it would save you from pulling the bullets and re loading the cases.

Before all of the new bullets, lots of people found that the Match King was the most accurate bullet, but not the best performing hunting without doing something to it.

I haven't used them for hunting in years, but if I had to, I could by trimming the Meplat. it is just a way to use them if you want to. Once they are trimmed, they perform well especially at long distances.

Just a way to utilized what you have.

J E CUSTOM

That's a great idea, I will definitely try that but probably shoot them out of my Sako as I would like a little faster bullet in my AR 10.

 

[cohunt]

I too have a lightweight 16" AR10 variant that I run suppressed (just over 6 pounds with optics- sans suppressor)

I run the 178eldx @ 2475fps--- I have tried numerous powders and bullet weights and always come back to the 178eldx for downrange energy and less wind drift (yet more drop than lightweight bullets). At my altitude It will still retain 1000ft lbs out to 800 yards with this combo and it holds an mpbr of 270 yards when zeroed just over 2.5" high at 100Y

if you decide not to shoot those SMK in your short barrel you might try the eld-x for reliable lower speed expansion

 

[HARPERC]

Try the 143 Lever Hammer if it's as close as it sounds like. Easy work up, generous HP.