Reloading Share techniques for reloading, where to get the hottest in reloading equipment and learn how to reload from fellow hunters.

6.8 spcii

Old 05-05-2015, 09:28 PM
  #1  
Nontypical Buck
Thread Starter
 
super_hunt54's Avatar
 
Join Date: Feb 2015
Location: Illinois
Posts: 3,695
Default 6.8 spcii

Ok guys and gals, It looks like I may have a hog hunt coming up in a couple weeks that may require a bit of over 100 yard shooting. So I think I am going to drop my Grain down from 130gr Interlocks to 100gr Accubonds. Switching to the Accubonds because the only Hornady in 100 is GMX that is suitable for Hog and I don't particularly like the GMX in the smaller grain weights for penetration. Doing the grain drop for a bit more speed (figure around 350 to 450 fps more)

Any AR 6.8 SPC II guys out there with experience in this load variation? Barrel is 18 inch mid Shilen, DI operated. Wont be using suppressor. From what my buddy said the landowner believes the hogs will be in the 150 to 200 pound ranges. Said he did see a couple of beef eaters that looked like they may go 250+ so I want a good bullet that wont blow up on a shoulder in case we can get across the field without being sniffed out and my range is close up and personal! But I need the added speed for opening up at 200 yards. I have a couple of weeks for load development and accuracy testing.
super_hunt54 is offline  
Old 05-07-2015, 11:32 AM
  #2  
Nontypical Buck
 
Nomercy448's Avatar
 
Join Date: Oct 2009
Location: Kansas
Posts: 3,898
Default

So you're dropping the bullet weight to gain some speed for 200yrd shooting? That doesn't really compute.

A 130grn with a ~.400 BC at 2500 will have about 8" more drop at 600yrds than a ~.300 BC 100grn at 2800fps. Zeroed at 150, there's only about 1/2" difference in drop between the two at 200yrds, and about 3" difference at 300.

Alternatively, the 130grn pill will hit with over 20% more momentum at 300yrds, better for punching through hard stuff and knocking hogs down.

I've loaded the 6.8 from 85 up to 140's, truth be told, any of them are going to hit hard enough to handle your 100-200lb hogs comfortably.

Zero at 150-180yrds and you'll be clean to 200yrds MPBR with ease out of either bullet.

Now, that said, the Accubond isn't going to blow up on you. Weight retention for the accubond at 6.8spc speeds is rather good, expansion won't be huge, but sufficient.

Then again, maybe I'm biased - most of my piggies have been killed with a 22cal 50grn V-max or 60grn Partition. The 6.8 in any flavor is a lot more hammer.
Nomercy448 is offline  
Old 05-07-2015, 12:50 PM
  #3  
Nontypical Buck
Thread Starter
 
super_hunt54's Avatar
 
Join Date: Feb 2015
Location: Illinois
Posts: 3,695
Default

It's not the speed for zero I am worried about Mercy. It's the drop off at range. I just want to make 100 percent sure I have plenty of speed at impact for opening up. The interlocks I am using now tend to not open up at around 220 yards+, with the load I have that is the most accurate, as I would like them to. I figure if I go to a lighter bullet weight and pack in about 350-450 more fps I can get a more reliable opening for dead hogs. Don't forget that they way we go after them is in groups so head and neck shots aren't very good options for scattering hogs. Shoulders and ribs are the target so I need a tough bullet that I know will open up reliably. Since I am only getting 2380 at the muzzle with the 130's, at 250 yards it is getting to the no go point.

If I remember correctly Mercy, you have an 18 inch 6.8 so your loading data for 100gr would be highly appreciated since you have similar rifles to mine. I have about every kind of powder that 6.8 books recommend. Benchmark, H322 (currently my powder for the 130's), IMR 4198 and 3031, and RL7. I want to run a little hot but not TOO hot. I figure if I can get up to 2750 with a good BC bullet like the AB then I should have more efficiency at longer range impact.
super_hunt54 is offline  
Old 05-07-2015, 03:32 PM
  #4  
Nontypical Buck
 
Nomercy448's Avatar
 
Join Date: Oct 2009
Location: Kansas
Posts: 3,898
Default

Are you showing pressure signs with that load at 2380fps? Seems a bit slow, even for 130's. I've gotten mid 2400's out of 130's in 16" tubes, and have seen data claiming 2,600 out of 16's. You don't get a LOT with the extra 2", but I think there's more advantage to be gained for the heavy pills. 2,380's pretty mild - I'd be interested to hear if you're really at the top end of your pressure there.

I'm working up some new brews for my BHW 6.8, I'll share once I find a sweet spot. Keep in mind, however, that Black Hole barrels use 3P rifling, that tends to run lower pressure and higher velocity, and I'm running a heavy buffer with an adjustable gas block, so you may not be able to match my velocities at safe levels with your Shilen. My "go-to" for 6.8 tends to be H335. Fast and good metering. I'm not going quite as heavy with my bullets these days, have a bunch of the 100 AB's and 110 Vmax's and TTSX's, a few hundred 120SST/Interlock's that I'll be burning up to see what this new barrel likes best.

Here's some more info on the reality I was trying to point out - Speed can never out-run aerodynamics. (stealing Ridge Runner's quote there).

The .323 BC is giving up a lot of aerodynamic disadvantage to the .460 BC Interbond SST, so that 300-400fps advantage is almost completely gone by 300yrds. 400fps difference at the muzzle has already closed to ~180fps by 200yrds, within 100fps of eachother at 300yrds, and they're running equal speed by 400yrds. Only about 1.5" between the two for drop at 250yrds for a 150yrd zero.

So I don't think you're really going to see a super significant difference in expansion at 200-250yrds, other than the general difference in the Interlock and Accubond itself.

Keep in mind - the 130 Interbond SST isn't designed for the 6.8 - it's not made to expand under 2k, so it's not really surprising that it didn't expand for you when it makes contact at 1800fps.
Nomercy448 is offline  
Old 05-07-2015, 03:48 PM
  #5  
Nontypical Buck
Thread Starter
 
super_hunt54's Avatar
 
Join Date: Feb 2015
Location: Illinois
Posts: 3,695
Default

I was using Interlocks not Interbonds. I really don't like the SST's, had a couple fail on me at close range out of my 7mm.08, blew up big time on shoulder. And I've had a few run in's at 240 yards with the 130 grain and they didn't open. One It punched through, killed the hog, but it was hell finding it with just 2 little .277 sized holes. They are absolutely perfect under the normal conditions we hog hunt but sometimes, as any hunter can tell you, it just aint friggin normal!

And no, no pressure signs. I'm not running it as hot as I could because the load I have cooked up is by far the most accurate. Any more and my groups open up significantly.
super_hunt54 is offline  
Old 05-07-2015, 04:07 PM
  #6  
Nontypical Buck
 
Nomercy448's Avatar
 
Join Date: Oct 2009
Location: Kansas
Posts: 3,898
Default

I mistyped the "Interbond SST," meant to say Interlock SST, which still wasn't right for what you're using...

I did make the assumptive leap that your shooting the Interlock SST's, not the "old school" Interlock SP - My bad!

Even with the IL-SP, it's a .406 BC, vs. the 100AB's .323. Less drastic of advantage, but still a more aero bullet, with a lot more punch on the business end.

But the Interlock SP is definitely NOT designed to expand at 6.8spc velocities. It's a .270win bullet, not a 6.8spc bullet.

The low BC's of the lighter weight "mag friendly" 6.8spc bullets are really what frustrate me about the cartridge. But it's nice to be able to get fat heavy bullets into mag length.
Nomercy448 is offline  
Old 05-07-2015, 06:02 PM
  #7  
Nontypical Buck
Thread Starter
 
super_hunt54's Avatar
 
Join Date: Feb 2015
Location: Illinois
Posts: 3,695
Default

Yep which is why I need to switch. As I said the performance is absolutely fantastic at the usual ranges I get shots on hogs. If I know for a fact that I'll be at longer ranges then I use the AR10 7mm.08 but that rifle is set up for longer ranges and not that fast handling for the hog groups up close and personal. This trip I may not be able to get up close or I may be able to. The land owner says they are all over the place and rarely predictable and since he has larger fields I want to be prepared for both.
super_hunt54 is offline  
Old 05-07-2015, 06:24 PM
  #8  
Nontypical Buck
 
Join Date: Feb 2003
Location: Eastern wv
Posts: 3,619
Default

try a hornady 110 gr hollow point, they are designed to run at 270 win. velocities, and I've had excellent results using them in the 270 on deer, slow them down a bit and they would work well on hogs.
RR
Ridge Runner is offline  
Old 05-14-2015, 01:21 PM
  #9  
Nontypical Buck
Thread Starter
 
super_hunt54's Avatar
 
Join Date: Feb 2015
Location: Illinois
Posts: 3,695
Default

Found a great load for the 100gr Accu's but had to do a little cheating. went .5 grain over and the COL is .025 over the recommended max 2.260 at 2.285. Went with 31.5gr Benchmark. MV is right on 2765 average over a 10 shot spread. Accuracy was a very respectable .265" group with the first 5 (3 in one ragged hole and 2 just off) Second group was .272" with pretty much the same thing. Me thinks the puppy likes it! The other 3 loads I had fixed up performed moderately "okay" but this one was spot on just what I like.

Give that load a try out of your BH barrel Mercy when you have a chance. No pressure signs from my Shilen so your's should handle it even better with about 5-8% more speed!
super_hunt54 is offline  
Old 05-14-2015, 11:25 PM
  #10  
Typical Buck
 
Join Date: Oct 2011
Location: Jacksonville, FL
Posts: 515
Default

I wish I could find benchmark in my area. Heard nothing but great things. H322 works ok for me though, but wouldn't mind trying benchmark.
JGFLHunter is offline  

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.