168gr smk

[eddiesindian]

Found couple of boxes of 168 smks I had laying around. I used to use them in my gas guns but have since sold all my 308 gas guns. Been looking for a load to replace my 175SMK with 4064 to lighten the umph just a tad so I figured I'd load up the 168 smks with some varget for my model K 1-10 24inch tube and , after load development, low and behold pay dirt. There making 1st round hits on a 7 inch metal swinging targets at 1018 yard's.
With that said I loaded up some more and while double checking my oal I noticed a change. After my diagnosis, I discovered my problem. Apparently, I opened another factory sealed box of the 168 smks to finish the rounds I was reloading. Wouldn't you know it. There's a 0.20 difference on the bullet from base to ogive from one box to the other. Different lot numbers.
I'm aware of the 168smk having issues going transonic and becoming unstable that of which I never had problems with that at my elevation and speeds when I was using them in my gas guns.
I'm sure sierra redeveloped the bullet to help in the transonic issues but I was never aware of it.
This maybe old news to some but it's new news to me.

[Robinhood]

Or could it have been the machine was set up differently after a run of different bullets?

[eddiesindian]

Very possible but if that's the case I'm sure it pist off a lot of shooters. I'll find out soon. I've got a box of 500 comming,I'll mic those and see what gives. Those boxes I had laying around for 5 or so years so who knows

[Robinhood]

Give me the dimension you got and I will measure a couple of lots.

[eddiesindian]

Using the hornady headspace gauge 8-30 insert for 308 caliber, I'm getting a 0.608 reading from base to ogive. The other box which I presume must have been the older box gave me a reading of 0.628.
I'm almost tempted to give the boys over at Seirra a call.
Seeing as how all i had to do was reset my seating die to get my oal...I have no issues with the difference. I merely have questions. Like I said, it may be old news to some but new to me.

[eddiesindian]

You know what I find peculiar about this hole 168gr smk saga is that I was merely bored and decided to prep some old lc brass,....cut to length, turn,anneal etc...to load up the 168 smks for the heck of it. I had about 3 lbs of Varget laying around that of which I stopped using because I couldn't find it. Low and behold, the dam load shoots lights out. What's adds more icing to the cake is that the local civilian/military gun range recently went liquor free by order of the commander. Its a real nice place to order up some grub and have a couple of cold ones but not no more. They've lost sales so they decided discount reloading components that they've usually sold for full retail plus. They had 8 lb ers of Varget going for $170 out the door. Couldn't say no to that

[Texas10]

Sierra started tipping some of their bullets a while back. Are the newer ones tipped? That's gotta change the OAL a bit.

[eddiesindian]

Negative

[eddiesindian]

Years back there was documented information of the 168smk getting wobbly while going transonic. Only thing I can figure is the sealed box,s I had may have been newly designed bullets by sierra for the 168smk instability while going transonic. At a quick glance, the bullets look identical, but if you look closely, you can easily see that the new design has more of a secant formation with a change in the bearing surface as well.

[eddiesindian]

Update FWIW.
I received 3 new sealed box's of 168smk. I miced those and low and behold, they too gave me different readings from base to ogive. 3 different lot numbers, 3 different measurement readings.
You'd guess there called match kings for a reason or maybe not.

[69gen1]

Update FWIW.
I received 3 new sealed box's of 168smk. I miced those and low and behold, they too gave me different readings from base to ogive. 3 different lot numbers, 3 different measurement readings.
You'd guess there called match kings for a reason or maybe not.

For what it's worth I see it quite often big diff in oal and ogive measure. load to your std .and move on ...I found the hornady not quite as bad 223 and 308 sometimes no diff at all plus little cheaper.

[eddiesindian]

Did that a long time ago. Change in poi was my outcome. Enuff for me to warrant load development again. A little time consuming but it is what it is. I'm shooting these up then it's off with the 308 barrel and going 284 winchester match..