311290 in the 308 Winchester using BLC2 Powder

[MUSTANG]

This thread will explore loading the 311290 style boolit using BLC2 Powder. Because of the bore rider nose design; I decided to gas check the boolit and only coat the driving bands of the boolit with Eastwood Blue powder coat (Dry Method) similar to what 405grain is doing in his post Hybrid Boolits at https://castboolits.gunloads.com/showthread.php?423448-Hybrid-Boolits

The first test was conducted back in early February of 2022. The specs for that test were:

Rifle: Remington 700 ADL Varmint .308

Barrel Twist: 1 in 12

Wind: 15

Temp: 40 degrees F.

Boolit: 311290

Ballistic Coefficient: .305
Brinnel Hardness: 9.8

Bullet sized: .309

Alloy: 96% Lead, 3% Antimony, 1% Tin

Bullet Lube: Driving Bands coated with Eastwood Blue
Gas Check: Ameri-max Aluminum 0.14”

Powder: BLC2 30 Grains

Primer: CCI-34

Case: Mixed military and commercial Brass

OAL: 2.845 Inches

Distance: 100 Yards.

10 Shot Group Size: 3.578 MOA.

296996

[MUSTANG]

The next test was shot today. I still used an Eastwood Powder Coat on the driving bands only, aluminum gas check, but sized larger to .310 inches. I also extended the boolit further out in the case at an OAL length of 2.875 compared to the previous 2.845 and used a Dacron filler. This allowed the nose to fit further into the chamber; bolt closing had a slight resistance at this length. The boolit CAN NOT be any longer in my Remington 700 Winchester because it would not have the clearance to extract when cycling the bolt if the round is not fired. These changes resulted in a smaller group than fired back in early February.

The specs for todays test were:

Rifle: Remington 700 ADL Varmint .308

Barrel Twist: 1 in 12

Wind: 5

Temp: 45 degrees F.

Boolit: 311290

Ballistic Coefficient: .305
Brinnel Hardness: 9.8

Bullet sized: .310

Alloy: 96% Lead, 3% Antimony, 1% Tin

Bullet Lube: Driving Bands coated with Eastwood Blue
Gas Check: Ameri-max Aluminum 0.14”

Powder: BLC2 30 Grains

Primer: CCI-34

Case: Mixed military and commercial Brass

OAL: 2.845 Inches

Distance: 100 Yards.

10 Shot Group Size: 1.979 MOA.

296997

[DonHowe]

Following this with interest. I have an old Ideal 308290 that casts big enough to size .311". Shoots well from a Remington 8-43 gov't 4 groove barrel.

[MUSTANG]

I shot two test groups today. The first was the 311290 with only the driving bands coated - the nose remained uncoated. I used a 30-06 case with each boolit inserted nose 1st into the 30-06 case to keep the PC powder off the nose. I then swirled and rubbed the base of the boolit on the bottom of the plastic tub until the bands were covered, then cooked for 40 minutes and air cooled. Gas Check applied before powder coating. Sized to .310 inch. These bolts had to be seated deeper than the fully powder coated - suspect that the coating was much thicker in the trnasitionarea to the nose because of the technique used to powder coat. Two of eight rounds were not fired because they would not chamber (Due to Fat transition area?)

The specs for todays bands only coated test were:

Rifle: Remington 700 ADL Varmint .308

Barrel Twist: 1 in 12

Wind: 10
Temp: 30 degrees F.

Boolit: 311290

Ballistic Coefficient: .305
Brinnel Hardness: 9.8

Bullet sized: .310

Alloy: 96% Lead, 3% Antimony, 1% Tin

Bullet Lube: Driving Bands coated with Eastwood Blue
Gas Check: Ameri-max Aluminum 0.14”

Powder: BLC2 30 Grains Dacron Filler

Primer: CCI-34

Case: Mixed military and commercial Brass

OAL: 2.855 Inches

Distance: 100 Yards.

10 Shot Group Size: 7.502 MOA.

297451

[MUSTANG]

The Second test group today; the 311290 boolit was fully coated in Eastwood Powder using the Table Method. then cooked for 40 minutes and air cooled. Gas Check applied before powder coating. Sized to .310 inch. Nose was sized to .301 using a Lee Bullet Sizer, turned two full turns into the RCBS Rock Chucker to size the nose only.

The specs for the test were:

Rifle: Remington 700 ADL Varmint .308

Barrel Twist: 1 in 12

Wind: 10
Temp: 30 degrees F.

Boolit: 311290

Ballistic Coefficient: .305
Brinnel Hardness: 9.8

Bullet sized: .310

Alloy: 96% Lead, 3% Antimony, 1% Tin

Bullet Lube: Driving Bands coated with Eastwood Blue
Gas Check: Ameri-max Aluminum 0.14”

Powder: BLC2 30 Grains Dacron Filler

Primer: CCI-34

Case: Mixed military and commercial Brass

OAL: 2.855 Inches

Distance: 100 Yards.

10 Shot Group Size: 1.749 MOA.

297452