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
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
