Switching from 175 Sie HPBT MK to 180gr Sie HPBT MK?

[DynoDuck]

Hey there Guru's.

I've nearly run out of my supply of 175gr Sie MK. I am seeing pleanty of 180gr Sie HPBT on the shelves online and in a few local shops and not finding my 175's anywhere. And when I do... They want the buyer to drop trow and ready themselves for the butt hurt,

My Rig is a Blueprinted Rem 700 SPS ACC-SD, 1-10 Twist 20" barrel with an 11 degree crown, Manners TF4A Chassis, Timney 510 Trigger set to 1.25lbs, Gemtech Tentioner QD Mount (Gemtech Quicksand), and Millett TRS-1 4-16x50 (My Loupy Mk4 zooming ring went limp, sending it in for repair.) and a Vanguard Equilizer 1QS Bipod.

I'm able to get consistant dime sized, 5 shot groups at 200 yards with my current load. 44gr Varget, 175 Sie HPBT MK, Lapua Brass, Winchester LR Primers at 2.865 OAL. My Remmy is happy with this load, and my mags hold the rounds nicely. I don't know the velocity as my chronograph seems to have taken an extended winter nap. Time to buy a new one this year. If memory serves me, and these days its hit or miss, I want to say it's 2565 fps out of the barrel at 10 feet to the first sensor of the chrono.

So, my question is does anyone have any experience with the 180gr Sie Mk? My understanding is that these were made for extended ranges. I'm unfortunately limited to 200 yards. 300 if I decide to play the part of Bruce Cambell in Army of Darkness and clear another hundred down the fence row. I'm just too lazy to do it I guess. lol...

How much will that extra 5 grains of weight affect my accuracy? I can go lighter. But when I add my supressor to the set up, the lighter projectiles aren't as consistant as my 175 gr. I have some 168gr Sie Mk here, again they don't perform as well with the "can" on.

All in all, I'm looking for advice on the 180gr or a 175gr likeness.

This setup is mainly a hole puncher, Coyote punisher, Hog killer, and back up weapon for Dept. SRT usage.

Thanks much in advance.

Rob

 

[SWThomas]

Powder Valley has 175 SMK in stock.

 

[roggom]

Grafs 175 are the same, just a little darker. They are SMK seconds that just weren't "shiny" enough.

https://www.grafs.com/retail/catalog/product/productId/26343

 

[ArmyJerry]

I been looking at these 180's also, wondering the same as you DD.

 

[BIPMaster]

OK Weber | Competition Rifle Parts has 500 175SMK in stock for $153.

 

[mdmp5]

I've wondered about the 180 SMKs for years myself. I think the 180s and 175s are almost identical as far as BC goes. I would think they are pretty much interchangeable.

 

[Thump_rrr]

I've been using 180's for 3 years in my Savage 10BA. 24" barrel 1-10" twist.
42.3gr of Varget in Lapua cases with BR-2 primers set at 2.800 which is 0.020" off the lands in my rifle gave me 2610fps.
5 shot 100y group.

 

[DynoDuck]

Thanks fellas!

I'll order my old faithfuls, and pick up the 180's to test out. I'm liking what Thumb_rrr's producing. I'm running a 20" vs. his 24" which shouldn't be the end of the world. A little tweaking my load data and all should be well.

Again, Thank you.

 

[RobertB]

For those distance your GTG. Don't be scared that it will be much different. It wont be. You can do 168 SMKs too with great results at the close range. THey are an incredibly accurate bullet within 750 or so yards.

 

[Niles Coyote]

I tried some 180smk's a year or two ago and they shot every bit as well as 175's, rifle used was a 1:12 R700 Tactical. I used varget and the load that shot the best was 1/10th less than my 175 load... 44.4 vs. 44.5 and IIRC velocity was 15-20fps less. Per Bryan Litz's book the BC is just above the 175 but inside 800 where I was using it IIRC, it stayed close to my 175 data. I read somewhere that it was highly regarded competition bullet until the design was changed to share the same boat tail as the 168 smk.

Some old threads on it.
http://www.snipershide.com/shooting/snipers-hide-reloading/67610-175-vs-180-a.html
http://www.snipershide.com/shooting/snipers-hide-reloading/108398-smk-175s-smk-180s.html

 

[HodgdonExtreme]

A quick recap on the background of the 180s:

Back in the day, they were excellent and highly regarded. Then Sierra changed the design. Design changes included shortening and sharpening the boat tail. It is the same, or very nearly so, to the 168smk boat tail.

I used to shoot them. I found the 180smk to often be wildly inconsistent out past ~900 yards.

 

[M40_A1]

Powder Valley has 175 SMK in stock.

Yes, and their price is good. BUT, when I got mine (500 pkg) it was shipped in a box that was only slightly bigger than the Sierra box, and only padded on two sides. I don't know how many times that parcel was dropped, but certainly it was, as one corner of the Sierra box had burst open and some bullets were floating around in the shippin box. I had to go through every single bullet to cull out the damaged ones, and there were many.