Testing Cutting Edge Bullets in 338 Win Mag

[merbeau]

In my initial effort to start building a load for my 338 Winchester Magnum, I noticed that Cutting Edge Bullets (they are all copper) makes a 200 grain hunting/match grade bullet and decided to test it first.

Firearm: Rifle is a 338 Winchester magnum configured in a 1996 Browning A bolt II Medallion having a walnut stock with a free floated 24 inch barrel and a 1:10 twist. Valdada two piece base and Warne rings were used along with a Bausch and Lomb 6-24x40 scope. The rifle has a BOSS system and it was not initially used for testing. Set at a nominal 3.0 as recommended by Browning and left at that setting for all testing.

According to the Cutting Edge [https://cuttingedgebullets.com] they produce a .338 caliber MTH 200 grain Match/Tactical/Hunting all copper bullet that is 1.420 inches in length, has a G1 ballistic coefficient of 0.570 and a required twist rate of 1:10 or faster.

Components: Brass used in the testing was Norma custom. Primer used was Winchester Large Rifle Magnum. Dies used where RCBS X sizing die and seater.

Testing: Two slits were made in the neck of a virgin piece of brass and a bullet was inserted and slowly closed into the chamber. The bolt then was opened carefully and the case/bullet removed. This is supposedly the point of bullet touching the lands which was 3.475 inches. After checking with Cutting Edge Support they recommended since this was a MTH style bullet to seat the bullet 0.025 inches deeper than the land COAL.

At their recommended depth the round still functioned in the magazine. I assume since they offer seating depth recommendations, the bullet must like to be jumped. The final testing COAL was 3.450 inches.

Bullets were seated half way into the case and then rotated 180 degrees to help with keeping bullet run out minimal.

Powders initially tested included IMR 4831, IMR 4064, IMR 4350, and Alliant RL 17. All initial testing with powder was started at 0.5 grains less than the maximum load and then 4 grains in 2 grain increments for testing. For example, the maximum listed for IMR 4831 is 74.5 and testing started at 70.0 then 72.0 and 74.0 grains. If a potential load was identified (around 1 MOA) then another test was conducted by varying the load +/- 1 grain to see if there was any improvement. Accuracy was predominant over velocity.
Initial testing was done at 100 yards using Bald Eagle match rest and leaf back rest. Groups with no vertical difference were preferred. Three shot groups were used in testing except when changing powders a fouling shot was included.

Results: At testing IMR 4350 at 71.5 grains gave a potential group of 1.2 MOA with little vertical dispersion. Then testing at 72.5 grains produced a group of 0.75 MOA. Then the BOSS system was adjusted from its initial setting of 3.0 (from Browning web site) and after moving three 0.1 clicks (setting now 3.3) the group shrunk to 0.55 MOA (Final Testing attached figure). This load was then chronographed and came in at 2924 fps. IMR 4350 was selected as my go to load.

I am very pleased with the performance of the Cutting Edge bullets and did not notice any more copper fouling then what I usually observe running a patch after cleaning with Montana Extreme copper fouling removal solvent. It was somewhat of a concern since this bullet rides the lands with a ring that engages groove. Obviously the observation was empirical.

The only issue that may come up is the damaging of the ring. The bullets come in a box with compartments for each bullet. I wonder if carrying rounds loosely would damage the ring and thus not allowing a good gas seal.

At some point I plan on testing this load at 250 yards

Robert

[black mamba]

Sounds like a fantastic load and cartridge.

[Dufus]

I have found that the Cutting Edge bullets DO like a good jump to the lands. Since they have a driving band, there is less upset when the bullet contacts the lands and can produce more velocity than a conventional bullet with less pressure.

They also are devastating on game. Very good bullets IMO.

[Clark]

I got 338 Nosler Partition Gold 250 gr for 10 cents each in 2008
http://thefiringline.com/forums/show....php?p=2901824
I got Federal Fusion 338 200 gr for 31 cents in 2014.

Both lifetime supply buys. I own two 338WM rifles and have the reamer.
I went to the range in 2008 and fired a half dozen groups.

I have not managed to draw another elk tag since.
338WM interest waned.
But I have a pending elk drawing status I should find out about this week, so I could become very interested in the 338WM again.

[FrankenMauser]

Thanks for the report.
I've been curious about their bullets, but it can be difficult (for me) to justify the cost.

Now that I have a few more things that use rather expensive bullets, almost exclusively, maybe it won't be so difficult to try the CE bullets in something.

Both lifetime supply buys. I own two 338WM rifles and have the reamer.
I went to the range in 2008 and fired a half dozen groups.

I have not managed to draw another elk tag since.

Same here. ....But it was a different cartridge, and the species was/is Antelope.


Lesson learned: Never build a single-species rifle. (Even if you justify it with "well, I could use it for XX and YY, too," if you're really building it specifically for one species, then you'll never hunt that animal again.)

Maybe I should sell that rifle.
Family heirloom (action). Great barrel, but hate the action. Really should keep it. But now it just angers me. Could fix some, but not all, of the irritation with a new stock. But there's not much point in keeping that cartridge now that I have other choices. Decisions...

[merbeau]

Thanks to all that responded. DUFUS glad to see you confirmed CE bullets like to be jumped. According to Cutting Edge's website these bullets are built like projectiles shot out of battleships in WWII which apparently used a copper ring to engage the rifling.

Yes, cost is a factor; however, I did not shoot a lot of rounds per year out of any one rifle so it is not a huge strain on my pocket book.

I have tested Cutting Edge's 6.5 mm MTH 120 grain bullet in a custom built rifle in 6.5 Swede using the same testing methodology that also gave me great results. This rifle is my favorite to shoot.

Many thanks again to all that replied and good shooting

Robert

[Clark]

No elk tag in 2015.
Put away the 338 for another year.