Selection and Testing of .308 Match Grade Bullets for F-TR Competition By Jason Hale

F-TR Rifle Competition is F-Class Competition where the TR is Target Rifle in .223 or .308 Winchester. At many matches, F-TR competitors are restricted to bi-pod, ruck or sandbags, though at the Nationals a front rest was allowed.

For me and what I’ve studied, its high mass high Ballistic Coefficient (BC) bullets that are most go-to projectiles (bullets).  You still have some folks shooting the 1:12 twist .308 Barrels that shoot between 155 gr and 175 gr projectiles, but mostly the heavy stuff.  Now at this point only one thing matters;

How does it perform with your chosen bullets IN YOUR GUN?  

My recently purchased 28” SS Criterion match barrel doesn’t seem to prefer the heavy 185 gr Berger’s, but I’ve only tried them with Varget, IMR 4064 is another option to try.  I like sticking with Varget since it works so well AND is more forgiving in variable temperatures.

If you’re just getting into competition shooting, you can’t go wrong with the 175 gr Sierra Match Kings.  You can load it to mag length. My factory barrel would shoot ¼” groups all day long.  The only downside is that when the wind is involved, it can get blown around quite a bit more than some of the other more recent slick BC offerings.  I am currently using the Sierra TMK’s and their shooting ½” at 100 yards and have a superior BC to the SMK.  So far I like them, but because the bullet profile is more secant, seating depth may be a hassle during tuning, but it didn’t take too long for me to find a depth that worked well and didn’t compress powder too much.

One item to point out, there is good reason that as a rule of thumb you don’t just try a new projectile which may be the same weight because if you seated them to the same length the depth into the case may change how compressed your charge is.  In addition, there are many other factors that are coming into play.  Spontaneous disassembly (BOOM) of your rifle and perhaps YOU is NOT GOOD.  It is wise to back off by 10% and then work back up while watching for signs of pressure.

Now for the true purpose behind this article, testing your loads.  Finding recommended loads out of a reputable loading manual is your job.  Here I will explain what I see in the data I’ve put together here.

 

The chart below represents testing and data gathered of bullets tested and corresponding results you may find of use.

Bullet Ballistic Coefficient Bullet OAL Base to Ogive COAL Seated to Lands Depth  Seated Into Case Previous Data/Comments
Berger 185 Juggernaut .283 G7 (Litz Verified) 1.342 0.698 2.923 0.424 Tried 1MOA best with Varget IMR 4064 an option
Sierra 175 Match King 0.495 G1 (averaged Sierra BC)

0.475 G1(Litz Verified)

0.243 G7 (Litz Verified)

1.230 0.661 2.838 0.397 2.800 (~0.040” off Lands)
Berger 168 Hybrid Target .264 G7

0.266 G7 (Litz Verified)

1.279 0.583 2.956 0.328 In Testing
Nosler 175 RDF .270 G7 1.330 0.651 2.950 0.385 In Testing
Sierra 175 TMK 0.523 G1

(Sierra BC)

0.522 G1 (Litz Verified)

0.267 G7

1.353 0.658 2.940 0.418 Current COAL 2.920 (0.020” off Lands)

Good groups 0.5 gr less than SMK due to pressure

 

Nosler 175 Comments/My Approach:

Looking at the Nosler 175 RDF’s you can clearly see that the tip is almost completely closed, which is awesome.  With Nosler’s claimed G7 BC of .270 which beats all of the other 175 gr projectiles, I can’t wait to try this in my current match rig.

Examining previous loads for the 175’s:

My current load for the 175 TMK is 43.0 gr of Varget (0.5 grains less than the SMK) which gets me to approximately 2600 fps.  Surface bearing length differences between the two may be the reasons which pressure signs are reached earlier in the TMK as it has a longer surface bearing length which ads friction.

Comments/Observations the Nosler’s 175 RDF:

One item that catches my attention is the length of the nose profile; it’s very long, which makes sense for a high bc bullet.  This makes it a great option for F-TR type shooters who single load and aren’t bothered by long rounds.  On the flip side, It also makes it difficult to load for magazine length without sacrificing case volume.  I may end up gaining some case volume over some of the other projectiles when loaded to the same length.  If pressures are marginal, I could eek out some addition velocity if accuracy wasn’t sacrificed.  One item examined for overall consistency is measurement of a 10 sample group for Base to Ogive length which can be associated with BC consistency.

 

Noslers numbers were right with the competition, including Berger.  Overall great observations for noslers new RDF.  I will likely start with Varget 8-10% below 43.0 gr and work up from there.  Since my rig is wired up for pressure readings, I’ll have some pressure trends to talk about soon.  I’ll be able to compare them to previous loads that I use as reference (Federal 175 gr Gold Medal Match and Black Hills 175 gr Match).

Comments on the Berger 168 Hybrid Target

There isn’t much to say about Berger other than two words consistency and expensive, or should I perhaps say expensive consistency.  Looking at the data compiled I may be able to drive this bullet to a higher velocity than the heavier 175’s without having to sacrifice anything.  The long nose profile may leave me some extra case capacity and the short bearing length may end up reducing friction from less contact with the bore.  In the end it all comes down to testing; if it doesn’t group, it doesn’t group.  Doing a lot of testing can sometimes be frustrating; but if you enjoy it, don’t give up.  Just don’t waste too much in components trying to get something to shoot.  You’ll know it when you’ve found a forgiving bullet.  This is why the Sierra Match King is still heavily used.  It’s just that easy to tune.  Alas, I am a tinkerer at heart and love a good challenge. I have access to Nosler 175’s for testing so we shall see if my rifle likes them. More later…

Good Shooting!

This entry was posted in Bullet Tests and Reviews., Reloading for long range target shooting., Rifle Tests by Ed Hale. Bookmark the permalink.

About Ed Hale

I am an avid hunter with rifle and Bow and have been hunting for more than 50 years. I have taken big game such as whitetail deer, red deer, elk, Moose and African Plains game such as Kudu, Gemsbok, Springbok, Blesbok, and Impala and wrote an ebook entitled African Safari -Rifle and Bow and Arrow on how to prepare for a first safari. Ed is a serious cartridge reloader and ballistics student. He has earned two degrees in science and has written hundreds of outdoor article on hunting with both bow and rifle.