Sierra .308 GameChangers (and some others now)

[Nature Boy]

I’m going to work up a hunting load with these new 165g Sierra hunting bullets tomorrow. I have a hunting trip planned in a few weeks and I hope to be able to report on how they perform in the field.

Since they are new this is all there is regarding Sierra load data



Of those powders here’s what’s in my inventory:

Benchmark
Win 748
H4895
Varget
IMR 4064
RL15
VV N140

What would you guys use and why? Help me narrow it down to one and I’ll get to loading

 

[Grumulkin]

I have found IMR 4064 has given me the best accuracy with a variety of bullets in various bullet weights and in several 308 Winchesters.

 

[Dwb1957]

I've had very good accuracy with 44.5 grs of re-15 using the Sierra 165 gr. SBT in four different rifles. Haven't tried going any higher I just stopped when the groups got tight. Have killed several deer with this load.

 

[Bat Rastard]

Varget has been good for me in 308.

 

[Blue68f100]

Of the powders you listed, Varget, 4895, IMR 4064 would be my top choices. I've shied away from RL-XX in general due to temp instability. I've always got good results till there was a big temp change >20F.

I've had good results with W748 ball powder too, you should use a mag primer with this powder if your planing on shooting in the cold. I have not used this powder with any bullet over 150gr.

 

[Legionnaire]

I have found Varget to be among the most flexible powders out there. Second choice from those you've listed, IMR 4064.

 

[Slamfire]

I earned my Distinguished in a 308 firing 168's out to 300 yards, and then 168's/175 out to 600 yards with IMR 4895 in a M1a. My velocities were tuned to the gas system, but the absolute first powder in the 308 I used to recommend was one of the 4895 series, that is IMR 4895/H4895/AA2495. The military cartridge was developed with IMR 4895 during WW2 and all the match ammunition was loaded with IMR 4895.



The 174 military bullet is vastly inferior in weight and balance consistency compared to modern match bullets, so these groups would be even better with our bullets. And I of the opinion that the bullet is more important than the powder, for accuracy considerations, and that many weird flyers are due to eccentricities with bullet concentrically and center of gravity. Just shoot enough Smallbore prone, and if it is not the wind, it is likely the bullet. I can go prone with good ammunition, and shoot Walmart 22 lr, I see the error in the cheaper stuff.

Shoot prone with sling groups like this in NRA competition (with irons) and it is hard not to believe that IMR 4895 works well in the 308. I think a bud did this one



I know this is one of mine:




Because H4895 is advertised to have more advanced coatings, I would try H4895 and then Varget, but then, either are so good... My bud's shooting F Class are using Varget with outstanding results. I tried it in a M1a, but it was a bit slow for the rifle I tested, I had case head separations, maybe it was just the lot. I But in a bolt gun, Varget is great!.. Maybe just try Varget. I ran some velocity tests with a 168, and I think anywhere around 43.0 grains Varget and 44 grains you will find an accuracy node.

Pre-64 M70
24 " Douglas Barrel 1:10 twist

168 Hornady Match 40.0 grs Varget wtd Lot 4295 Mixed LC WLR OAL 2.8
3 Oct 05 T = 88 ° F

Ave Vel = 2459
Std Dev = 16
ES = 56
Low = 2439
High = 2495
N = 10
rounded primers ten ring accuracy on MR-31 target

168 Hornady Match 41.0 grs Varget wtd Lot 4295 Mixed LC WLR OAL 2.8
3 Oct 05 T = 89 ° F

Ave Vel = 2530
Std Dev = 14
ES = 39
Low = 2509
High = 2548
N = 10
rounded primers, ten ring accuracy MR-31 target

168 Hornady Match 42.0 grs Varget wtd Lot 4295 Mixed LC WLR OAL 2.8
3 Oct 05 T = 89 ° F

Ave Vel = 2602
Std Dev = 20
ES = 65
High = 2633
Low = 2568
N = 10
flattened primers, X ring accuracy on MR-31 target

168 Sierra Match 43.0 grs Varget wtd Lot 4295 Mixed LC WLR OAL 2.8
3 Oct 05 T = 89 ° F

Ave Vel = 2660
Std Dev = 15
ES = 48
High = 2680
Low = 2632
N = 9
flattened primers, slight cupping into firing pin hole, v. good accuracy, easy extraction

168 Sierra Match 44.0 grs Varget wtd Lot 4295 Mixed LC WLR OAL 2.8
3 Oct 05 T = 89 ° F

Ave Vel = 2709
Std Dev = 14
ES = 45
High = 2735
Low = 2690
N = 10

flattened primers, slight cupping into firing pin hole, excellent accuracy, easy extraction


168 Hornady Match 45.0 grs Varget wtd Lot 4295 Mixed LC WLR OAL 2.8
3 Oct 05 T = 89 ° F

Ave Vel = 2757
Std Dev = 16
ES = 55
High = 2786
Low = 2731
N = 10
flattened primers, slight cupping into firing pin hole, excellent accuracy, 8 in one hole, probably max load

 

[Nature Boy]

My 308 F Class load uses 43.5g of H4895 and pushes a 185g Berger Hybrid 2,715 fps. I’ve tried several and this one always comes out on top.

Being that I’m after a hunting load I don’t need to push them that hard. Something between 2,600 and 2,700 should be plenty for whitetail out to 300 yards, which is my self imposed limit

I always reach for the H4895 first and Varget second, as a result these others never get used. Figured I let the consensus decide this time

 

[Slamfire]

Those are all good powders. It is objectively hard to prove a "best", as each one of those powders is the best in someone's rifle. Maybe, the "most best"?

 

[rbernie]

H4895.

 

[Nature Boy]

I decided to pick RL15, for no other reason than I haven’t used it in a while.



I loaded up 3 of each charge weight starting at 42.0 and going up to 44.5 In 0.5g increments.

I chose the longest OAL that would fit the magazine and that was 2.875. Here’s the delima with these long bullets. As you can see in the pic above, that puts most of the bearing surface well into the case and at mag length OAL I’m still jumping a LONG way to the lands.

Why does that matter? Well, my load test showed a potential node between 43.5-44.0, but the next step to get the most accurate load would be to play with seating depth. I can’t go any longer and fit the mag and I don’t want to push the bullet any deeper into the case. I’m kinda stuck.

I’m still going to load 10 at 43.7 and see what they do but I pretty much already know they will suck. I also know that I could likely get these to shoot tight knots if I got closer to the lands. That would make my repeater into a single shot. I don’t want to declare this cake a failure before it’s baked but I’m pretty sure they won’t work

I know my reworked FN SPR can shoot as I spent the first part of my range session breaking in the new Proof carbon barrel. I loaded up 50 rounds of 155 AMAX bullets in progressive mode on the Dillon using a safe 40.5g (+/- 0.2g).

After sighting in the new scope I proceeded to shoot, clean, shoot, clean until no copper was present and I was there after 25 rounds. Dispite the added variables associated with the break in and loading progressively, those rounds drilled a nice contiguous hole in the target.

So, I think I’ll need to pick a shorter bullet that gives more more leway for tuning the seating depth if I want the most accurate load. Hear are some potentials that I have in inventory compared to this new Sierra GameChanger



I also installed my Hellfire brake which really made this rifle a pleasure to shoot from the bench. I’m hoping to have an answer to what it shoots the best by tomorrow



As always, your opinions are welcome.

 

[Bfh_auto]

I'm seriously questioning the testing of 4064 that was done.

 

[Bfh_auto]

I decided to pick RL15, for no other reason than I haven’t used it in a while.

View attachment 812637

I loaded up 3 of each charge weight starting at 42.0 and going up to 44.5 In 0.5g increments.

I chose the longest OAL that would fit the magazine and that was 2.875. Here’s the delima with these long bullets. As you can see in the pic above, that puts most of the bearing surface well into the case and at mag length OAL I’m still jumping a LONG way to the lands.

Why does that matter? Well, my load test showed a potential node between 43.5-44.0, but the next step to get the most accurate load would be to play with seating depth. I can’t go any longer and fit the mag and I don’t want to push the bullet any deeper into the case. I’m kinda stuck.

I’m still going to load 10 at 43.7 and see what they do but I pretty much already know they will suck. I also know that I could likely get these to shoot tight knots if I got closer to the lands. That would make my repeater into a single shot. I don’t want to declare this cake a failure before it’s baked but I’m pretty sure they won’t work

I know my reworked FN SPR can shoot as I spent the first part of my range session breaking in the new Proof carbon barrel. I loaded up 50 rounds of 155 AMAX bullets in progressive mode on the Dillon using a safe 40.5g (+/- 0.2g).

After sighting in the new scope I proceeded to shoot, clean, shoot, clean until no copper was present and I was there after 25 rounds. Dispite the added variables associated with the break in and loading progressively, those rounds drilled a nice contiguous hole in the target.

So, I think I’ll need to pick a shorter bullet that gives more more leway for tuning the seating depth if I want the most accurate load. Hear are some potentials that I have in inventory compared to this new Sierra GameChanger

View attachment 812638

I also installed my Hellfire brake which really made this rifle a pleasure to shoot from the bench. I’m hoping to have an answer to what it shoots the best by tomorrow

View attachment 812639

As always, your opinions are welcome.

You could try one of the faster powders. Sometimes it will help it jump.
I hope you can force Gamechangers to work.
I bet your 155 Amax would drop a deer without trouble.

 

[Nature Boy]

I'm seriously questioning the testing of 4064 that was done.

You mean by Sierra for their load data? It does look odd.

 

[Bfh_auto]

You mean by Sierra for their load data? It does look odd.

Yes sir. I don't understand how they got better velocity with 4895 unless case capacity is an issue. If that was the issue, then Varget should have been slow also.

 

[Nature Boy]

I’ll spare everyone the math here and cut to the chase. To load at max mag length, the corresponding jump for these bullets would be:

165 GameChanger = 0.125
168 Berger Classic Hunter = 0.015
165 Nosler BT = 0.043

I just don’t believe you can get good accuracy jumping a bullet 1/8 of an inch to the lands

I find myself for the second time really wanting to like one of these new offerings from Sierra but disappointed that they just don’t work for me

I think I’ll go with the Bergers and see how they shoot

 

[Blue68f100]

How does the shape compare (jump to lands) to their original GameKing's (SBT)? The original GK's have always given me around 0.025"-0.035" when set to Sierra's recommended OAL.

 

[Nature Boy]

How does the shape compare (jump to lands) to their original GameKing's (SBT)? The original GK's have always given me around 0.025"-0.035" when set to Sierra's recommended OAL.

Unfortunately I don’t have any in .308 to compare (I have some in .358). The Berger Classic Hunter is a tangent ogive like the SGKs so I would expect them to be similar and more mag length friendly.

Also, if you look at Sierra’s preliminary load data I posted, they state the OAL to be the standard 2.800”. There’s no friggin way. That would push the bullet into the case past the ogive.

I’m going to give Sierra’s tech/CS a call this morning and see what they say. These are hunting bullets, not target bullets. They have to fit a magazine (most people don’t hunt with a TC Encore or Ruger #1). Having said that, they would likely work better in a long action cartridge, and if that’s the case, Sierra needs to say that.

 

[Nature Boy]

Talked with a tech at Sierra a while ago. The only thing he suggested is to try another powder. I’ll work up another test with H4895.

He also said to shy away from 4064 as they encountered pressure early (that’s why there’s such a short spread in the load data).

 

[Nature Boy]

Slight change in plans. I worked up a test with the Bergers and RL15, then I cracked open the Nosler book and selected their accuracy loads for the 165 and 150 BTs



I’ve used this before as a short cut and sometimes it works. We will see how it does.

The 165 BT calls for 46.5g of BL-C 2 (I used magnum primers). The 150 BT calls for 42.5g of VV N140.

Loaded 10 each and headed to the range.

PS: always work up your loads from low to max and don’t do what I did

 

[Slamfire]

Talked with a tech at Sierra a while ago. The only thing he suggested is to try another powder. I’ll work up another test with H4895.

He also said to shy away from 4064 as they encountered pressure early (that’s why there’s such a short spread in the load data).

I would love to have a pressure gage. Something simple, easy to use. They are seeing things that I will never see or detect with my crude pressure testing devices. Which are blown primers, sticking cases. I have to say, I would not have thought that IMR 4064 had early pressure problems, because, it has a slower burn rate. Just shows how little I know, since I cannot measure the phenoma.

 

[Nature Boy]

Post range results.

I’m putting bottm line up front here. These are my observations at this point.

1. The PROOF carbon barrel doesn’t perform well with bullets heavier than 155g

2. Dispite the marketing claims, the PROOF carbon barrel behaves more like a sporter weight barrel and less like a heavy contor barrel. It scatters shots if you don’t allow it time to cool.

I have a friend who recently sent his PROOF barrel back to the factory thinking there was something wrong with it because he experienced the same issues I note above

3. With the right load, I believe this rifle will consistently deliver 5 shot groups ~0.5 MOA, which is perfectly acceptable in a hunting rig....as long as I don’t violate 1 and 2 above. It’s just not a target rifle.

Here’s what I base my observations on. Before heading to the range yesterday, I loaded up 50 155 AMAX in progressive mode on my Dillon for the purpose of breaking in the barrel. I dialed the powder charge back and took whatever it threw and that was my load. I had some of those left over today and as I was waiting for a bench to open at 100 yards, I headed to the 200 yard lane and put these 5 shots into the target below.



Again, it’s a random load with +/- 0.2g loaded on a progressive press. It’s also a bullet under 165g.

Next, I shot the 165 Noslers at 100 yards. The first 5 on the left I shot it pretty quick succession. The ones on the right I slowed down and let the barrel cool. This is Nosler’s accuracy load for these bullets



Next I shot the Nosler 150 BTs using their accuracy load. They were better. It might be worth doing a load test with these.



Lastly, I did the load test on the Berger Classic Hunters. Much like the Sierra GameChangers, they were so inconsistent it’s hard to analyze the data. Here’s the target.



My next steps.

1. Keep working on a load that uses bullets under 160 and see if I can get something to shoot.

2. Have a talk with the gunsmith who buit this rifle (and 2 others that I shoot in competition) and see if he has any suggestions.

I think a .308 that can’t shoot bullets heavier than 155g is gimped and I paid too much for it to be satisfied with that. Maybe it’s too premature to draw conclusions yet.

It really is nice though. Fits me perfectly, comfortable to shoot and carry. Everything I was looking for, with the exception what I’m seeing in terms of performance

 

[Bfh_auto]

Wonder if the 150 E-tip would work. It would give you similar performance to the 165 class bullets.

 

[z7]

What is the twist rate of that proof barrel?

I am surprised at the lack of accuracy you are getting, for the price of that barrel it should shoot much better. I might put some factory match ammo through it just to double check how it shoots, then call the smith back

 

[Nature Boy]

What is the twist rate of that proof barrel?

I am surprised at the lack of accuracy you are getting, for the price of that barrel it should shoot much better. I might put some factory match ammo through it just to double check how it shoots, then call the smith back

1:10

I’m headed back to the range today with more loads to try, including a box of comercial Federal GMM 168g SMKs. I’ll hold off on making any more conclusions until I’ve tried everything I know to do.