Sierra Match King 155 #2156 Question

Joep17

Joep17

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Guys,
There is so much experience and thoughtful help on THIS PARTICULAR SECTION of Gunnutz, I would like some advice please.

After 35 years of loading and shooting at distances, I was convinced to try F Class this summer (I have now sold a kidney already to feed this new addiction).

Up until now, all the HB 308's I have had have shot the 168 SMK extremely well. I bought another one, a 700 SVF and it did not shoot the 168's well (about 1" 5 shot @ 100) so I went and bought 500 155's. When I went to measure the seating depth with my Sinclair tool, the bullet dropped so far in, I would need to seat it 0.10 BEYOND THE NECK to get close to the lands. There is not a hope in getting near the lands. I finally set them with an OAL of 2.94 and they are about 1/10" into the case.

At the range Sunday, they shot ok (about 0.5 to 0.7" for 5 shot @ 100). 32X Nightforce and the rifle has been bedded, crowned and a trigger job by Henry R.

Anyway, after all that rambling, my question is: How much accuracy am I giving up with the bullet seated so far from the lands? Should I switch to a 175 SMK?

Thanks for your kind and serious responses.

Best regards,
Joe P.
 
There's actually 2 155 grain SMKs, the 2156 that you have and the older 2155. The old one will reach the lands easily if you can get anywhere near them with the 2156s. Whether they will shoot better will cost you a sample pack to find out. The old ones shoot a lot better for me.
 
You might want to try the Berger 185gr saw some great results from fellows using them
in F/TR this summer
manitou
 
The big reason you aren't getting much accuracy from this gun is the long throat.

I have found that a bullet must fully engrave into the lands BEFORE leaving the case neck if there is to be any chance of sub MOA accuracy at LR. Sounds like you have a 4000rds throat right now.

Best option would be to set back the barrel, cut a proper chamber, load any bullet you want and live happily ever after - this assumes the factory barrel is of good enough quality to shoot sub 1/2 MOA in the first place.

Plan B would be to load a heavier bullet that is long enough to reach the rifling. This is likely in the 175 to 190gr class. Recoil goes way up though.

If you plan on the heavy bullet route, see if you can't beg borrow or steal a couple of heavies to test. If these bullets cannot contact the lands either, that rifle will never shoot.

Ideally, the bearing surface of the bullet should be at least 1/4" into the case neck and the ogive 10 thou OFF the lands. That gives you plenty of support and the bullet has room to get going.

Jerry
 
well I've never had a .5'' 5 shot group, I'd be happy with that!
I'm using the older 2155 but cannot reach lands either (mind you that is in a factory rem)
 
The Remington chamber throat was designed by a lawyer - not a shooter. The 175 might work properly. Sierra 190 would work just fine. try longer bullets before anything more drastic. The rifle might love them.

If it was mine, I would set the barrel back a half inch and cut a match chamber.
 
The long Lapua 154 may work better. Only testing will tell, as the American who came second in the Grand Agg at Connaught last year loaded the Lapuas .060" off lands. Theory doesn't replace testing. I've seen some rifles shoot the old Sierras better, but at the recent Mini Palma between Atlantic Canada and New England, 3 shooters shot 600/600 with new Sierras.

Regards,

Peter
 
My first precision rifle was an accurized Rem 700VS,

I shot Berger 175vld's, with a COL of 2.998 (40 thou back from the lands as I recall) and 44gn of Varget, Lapua brass, CCI BR2 primers. I did not experiment much with the load, in hindsight I could probably found a node at a higher velocity, but at the time I was happy with this.

I could not get any Sierra's at the time, so I am not sure how they would have worked out.

This load always shot well. The groups pictured below were routine.

I used this for precision matches out to 800 yards, and shot several 1000 yard practices. I eventually upgraded to 7MM to shoot FO, but this rifle with that load would have been fine for factory class.

Slide1.JPG
 
Thank you all for your knowledgeable and helpful suggestions.

For the club shoots, we have a sub category of F-Factory. I believe that if I set the barrel back, it might not qualify. The rifle only has about 500 rounds through it.

I started the summer with my 6.5-284 Cooper to learn with but I have since convinced 3 of my buddies to try the Factory class with their 308's hence my desire to go down to that class to shoot with them.

Interesting side note, I was wondering if anyone was going to come back and suggest Bergers. While everything I hear about them is fantastic, we do not have a reliable source. At any given time, WSS is sold out of the popular sizes. P&D in Edmonton always seems to have the popular Sierras in stock so that is why I am shooting them.

You guys have been great! Thank you so much for helping me out. I am sure I will be back with more questions.
 
I definitely second the motion to try Lapua 155 Scenars. They have a much longer bearing surface and are a longer bullet over-all than the 2156's (Which are much longer than the 2155's by the way) The Lapuas are a fantastic bullet and Peter always has stock.

The Berger bullets are very good, but I have always found them to be the most seating depth sensitive. I had very good luck with 178 grain Amax bullets in 308 as well.
 
Obtunded said:
I definitely second the motion to try Lapua 155 Scenars. They have a much longer bearing surface and are a longer bullet over-all than the 2156's (Which are much longer than the 2155's by the way) The Lapuas are a fantastic bullet and Peter always has stock.

The Berger bullets are very good, but I have always found them to be the most seating depth sensitive. I had very good luck with 178 grain Amax bullets in 308 as well.
Click to expand...

As Peter knows, I have a wide selection of Lapua bullets, given the long throat in that factory rifle the only bullets that shot well were, SMK 168, Lapua 167, Hornady 168 BTHP (COL 2.8) and the 175 gn bergers, I cannot see why the 175 SMK would not do well, I just did not have any. I tried 3 other 155 (Sierra, Berger, Lapua) none of them were impressive in my factory Rem700 VS
 
Question: which is more important- higher BC, or longer bearing surface? I ask because I'm thinking of trying the Berger 175gr Long Range BT with it's G7 BC of .264 and a relatively short bearing surface of .324, but I note that the Amax 178gr has a lower BC (.240) but a much longer bearing surface: .509
Thoughts?
 
For resistance to wind drift, BC is everything. Bearing surface (in this case) was an advantage as having more surface allows the bullet to seat further in the case for the given throat, but long throats are a curse in factory rifles and optimal seating depth is not always possible.

The longer heavier bullets tend to work better in factory guns because of the throat length.
 
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