I'm running 2 rifles both with a 1:10 twist, but I'm getting 1 MOA at best out to 200 yards with bullets ranging from 150 to 175 grains including 155 grain SST and 168 and 175 SMK's.  Loads include Lapua brass, CCI 200 primers, and several powders- IMR 4895, IMR 4064, RL 15 and VV N140.  

Based on considerable research it seems 1:10 twist barrels come into there own using bullets weighing at or above 200 grains.  Can anyone recommend a modern bullet design at 200 to 220 grains and powder combination that might produce better results?

Rifles in question are a Winchester Model 70 Coyote and Savage Hog Hunter in an MDT Chassis. I've not run into this issue before with Ruger M77,s, Howa 1500's, or other Model 70's.  Thanks in advance!

Try 168's.

41.5 grains of IMR-4895
42.0 grains of IMR-4064

I think all .308's should be 1:10 twist

https://hammerbullets.com/product/308-cal-166g-hammer-hunter/

These are a bit spendy, but they performed very well in my 1-10 twist 300 wm.

I looked into loading 220 SMK in 308 win years ago, but couldn't find any published data with that heavy of bullet. Some info on loads in this thread from members here:
https://www.ar15.com/forums/precision-rifles/220gr-308-Win-load/10-7204/

Here's load data for 220gr SMK. It would be my preferred bullet for accuracy...
https://www.xxl-reloading.com/.308-Win.-308-Winchester-7.62-x-51-.308-220gr-Sierra-HP-MatchKing

I really like the 190 SMK.

42.0 gr IMR4064
F210M primer
Winchester commercial case
190 SMK seated 0.020" off the lands.

It works out to at least 1,000 yards.  Of course 600 yards is about the minimum before I use these.

I experimented with 210 gr SMK and Bergers, including moly-coated 219 Bergers.  They were not as good - lower velocity.  There was no safe amount of powder that would make up for the speed deficit.

First post and all.

If it doesn't shoot these it's just the gun / brl not the twist.


My brother has an old remington 700 the police mdl that came in the McMillan stock.

That gun will only shoot 1.5" -2"

My 1:10s shoot factory 168 GMM around 7/8” @ 100 all day long off a solid position. 155 Scenars and 178 ELD also do fine. Either Varget or IMR-4895, seated 0.020” off lands and nowhere near max loads (don’t recall final charges).  My old 1:12 Sendero likes the 168 SMK over 4064.  

220s I reserve for .300WM.  My 1:10 .308 barrels are 20” or less so I haven’t shot anything over 190, so I don’t know limits for stability on the heavier, slower bullets.

Are these rifles properly bedded?  What about the scope rings, are they straight and tight?  Has anyone else shot them?

Is this a generic load, or are you tuning one special for each rifle? If generic, take your 1moa as a win. Neither are “match” rifles with big name barrels.  I don’t know you, OP, so I have to ask… Do you actually have a rifle+ammo that YOU can solidly shoot better with?

How’s your load development on charges and seating? Have you tuned these loads to having the charge down to a tenth grain? Barrel harmonics may come into play. Just moving the charge .1gr may make a dramatic difference.

I’d think 175 and heavier shouldn’t be “over stabilized”.

If you want to keep velocity up, maybe go to a 175+ all-copper bullet to increase projectile length and balance out the twist. Or work up some 200+gr traditional lead-copper bullets.

Have fun slinging 220s from a 308. Talk about “can’t get out of it’s own way”…

This why people should have hard copy reloading manuals! Took me seconds to look in the Sierra Manual and Hornady Manual.
Hornady has had 308 220 RN Data for years and I mean years! A guy I know hunted moose with the 220gr 30 Cal Hornady RN in his Winchester 88.
I think at one time Winchester had factory load with 220gr bullet in 308.
Same with Sierra years!

You did not try hard enough.  

Isn’t the 220RN shorter? With that heavy of a bullet you are pretty cramped on a 308.

Old thread on 220’s
https://www.ar15.com/forums/precision-rifles/220gr-308-Win-load/10-7204/

Of those listed I’ve used Reloder15 the most.  I want to say I was at 43.6gr for 168s and had the best accuracy results

I prefer 2000MR for ease of powder throwing and loading in bulk for matches but RE15 edges it out slightly

Honestly, I have shot better groups with a 20" scoped AR at these distances.  Rather than beat a dead horse, I'm going to start by rebarelling the Savage to a 1:11 twist with more barrel length-either 24 or 26 inch.  The factory barrel claims to be 20" but in reality it's closer to 18".  TypicallyI load enough test rounds to test new loads in multiple guns.  Given that I'm getting very similiar results from both rifles, my reloads are most likely not the issue.  Agree, swinging 220's is not the answer...lol

OP, if you want a modern bullet with good BC and that will work with 10 twist in 300wm, Thats easy Berger has a pile of brand-new 30 cal high BC bullets out, they have at least 20 bullets from 180 to 245, and include G7 BCs from as low as 2.63 to as high as G7 BC of .433......And their stuff is extremely consistent...

Attached File

OP, try the 190 SMK.  It is my favorite load.

200, 210, 220,... they are just too heavy for a 308 case.

With the load I posted above, I get 2600 fps; 1/2 MOA at 200 yards in testing from a 24", 1/10" twist, factory barrel (Remington 40-X).  

That accuracy figure is limited by my ability to shoot, not by the bullet.

Also, I have to wonder whether your 175 gr load just needs more work.

Wrong... I've got older books than you... Sierra 2cd goes up to 200gr, Hornady 2cd and 4th 200gr and 2 Speer books ...190gr.

OP asked for bullet recommendations to increase accuracy, so why reference a RN bullet?
 
You're right, I didn't try very hard. 168gr SMK do well in my rifle. I have several hundred 220smk and was wondering what to do with them...

What's your barrel length,  my 308 shoots the 155gr palma better than any bullet I've tried yet. I'm getting .400" 5 shot groups with a 20" all day at 2700fps.

Attached File

If OP is not developing this load for long range shooting, he will almost certainly do better (more accurate, flatter trajectory) with lighter, flat base bullets.

What are OP's objectives for this load development, do we know?  <-- going to re-read the OP's posts.

ETA -
"Based on considerable research it seems 1:10 twist barrels come into there own using bullets weighing at or above 200 grains."  

In the context of a 308 Win cartridge, this is incorrect.


Can anyone recommend a modern bullet design at 200 to 220 grains and powder combination that might produce better results?"

Implied  in OP's first post, a more accurate result is the "better result" he is after but no distance is given.  


Where heavier bullets are preferred is at longer ranges where their higher BC affords lower wind deflections.  The key to achieving that is keeping the muzzle velocity high.  Once the bullets gets too heavy (like 220 gr), muzzle velocity drops too much and any BC advantage is given up to lower initial velocity.  

I tested this using 190 SMK and 210 Berger.  Using a 308, the 210 was worse than the 190 because of the lower initial velocity.  The 190 SMK was much better than the 168 SMK at 600 yards but the 210 was not as good as the 190.

The 175 was supposed to have a combination of high BC and be just enough lighter than the 190 SMK to yield good performance at longer ranges with lower recoil (that 190 SMK load I posted is a stout load).  I changed cartridges before bothering with the 175 SMK, as none of them beat the 6.5mm and the 6mm to which I transitioned for long range.  

If OP is not after long range performance, there is no reason to go after heavies based on a "research" result which is false.  <-- sounds harsh but it is true.  

Would be good if we knew OP's goals.


Nonetheless, testing loads is fun and there is no proof like proving it to yourself.

I had a 1:10 Savage 308 back in the day that loved 180gr Sierra Game Kings on top of 42.2gr of IMR-4064...a little over .6 MOA. That same load shoots even better in a 1:11 twist SSG3000. That SSG loves it some Berger 185gr Juggernauts too.

Don't discount using a "hunting" bullet. They can be every bit as accurate as match bullets.

Not sure how a +200gr bullet would help in a 308 when the other bullets you've tried are known performers across a wide range of applications. I'd look at the torque of every single screw on the guns/scopes in question before going down that rabbit hole of rainbow trajectories.

If the barrel is decent quality it should shoot any bullet weight well, 1-1.5moa. It might prefer a heavy or lighter bullet but that is also dependent upon what you plan on doing with the loads. Heavys for punching paper out past 600, mediums for 600 and in, etc. In my opinion, the 308 just doesn't have enough case capacity to get the 180+ grainers moving fast enough.  One mistake I see many reloaders make is assuming you have to shoot heavy bullets for fast twist and light for slow (within stability limits). That just isn't the case. Especially with modern bullet technology. You can step way down in weight class, flatten your trajectory, and reduce recoil and still have incredible terminal ballistics. For example, 308win, 5 shots at 100yards, 110gr barnes TTSX. Run the data on this combo, it'll will out run a 257wby. Bonus, you can likely use the powder you already have that you use to reload your 5.56 ammo with.

While out current supply situation does not allow for much if any primer experimentation.  Primers in rifle do make a difference.

Back in the 80s shooting HP I could duplicate M852 using IMR 4895 - WLR - M852 brass.

For me today Varget and BR2 in Lapua brass is hard to beat with all kinds of bullets 168/167  / 175 / 185
N540 with A-Max 208's and Fed210M is nice too.