Review Of IMR 8208 XBR-Hogdon's New Benchrest Powder
On my third trip to the range, I shot another Bartlein barrel. This one features a 13.5 inch conventional twist. The bullet used was Bartís 65 grain BT. In this session I will use 31.0 grains of the 8208 XBR throughout. The variable that I will test is two different primers. (Wolf Small Rifle vs Federal 205ís)
The barrel used has more rounds through than the gain twist barrel used previously. I would not shoot this barrel in a big match. The reason that I chose Bartís BT bullets is that they performed best with N133 and I knew the best seating depth for that powder. This barrel performed best with the bullet jumping about 0.010.
The skies cleared and the temperature was 45 degrees. The skies were cloudless and the wind was from 7 to 8 oíclock at about 4 to 8 mph. Conditions were good except for some pesky mirage.
After firing one round to foul the barrel and establish zero, I proceeded to shoot two, 3-shot groups with loads having Federal primers. I did not have wind flags in place for the groups that I chronographed. The velocity average for those 6 rounds was 3221 and the SD was 12. The two groups measured 0.245 and 0.201.
Next, I fired two, 3-shot groups with the same load except these featured Wolf Small Rifle primers. The velocity was 3223 but the SD was an extremely low 3 fps. Accuracy was 0.114 for the first group and .201 for the second.
Earlier in the week I shot this same load in a gain twist Bartlein barrel. Both barrels were 21 inches long, but the GT registered almost 100 fps higher velocity than the 13.5 standard twist. Both were 4 groove, .237 bore barrels.
What caused the velocity difference? My guess is that the flat base bullets seated into the lands caused higher pressure than the boattail bullets jumping about 0.010 inch. Both bullets weighed 65 grains, but the flat base had a longer bearing surface.
After chronographing the velocity of the two loads, I set up the wind flags and shot one group with each type. With the Federal primer, I got a 0.142 group and the Wolf-primed rounds printed a 0.206. This barrel has served its time and is now ready for retirementÖif you know what I mean.
I returned home and decided to try one more barrel before submitting my findings to Dave Brennan. Next, I am going to try a Krieger barrel chambered for the 6XC cartridge. For data I e-mailed Lou Murdica and asked did he have any data for this larger capacity case. He said that he was shooting 36.0 grains behind a 105 gr. Berger VLD in his 6 X 47 Lapua. Since the Lapua case and the 6XC are almost identical (the XC has a large primer and the Lapua a small one), I decided to start at 35.3 and work up to 36.0 grains of powder behind the same bullet.
I loaded 3 rounds that were seated to jump about 0.010. I normally donít jump VLD bullets, but I may start after seeing the results at the range.
My first group with the 6XC was to zero the rifle. It consisted of the 105 Berger Target VLD pushed by 35.3 gr. of 8208 XBR. These are the ones that were jumped. Without the benefit of wind flags, they formed a 3-shot cluster that measured 0.171 inches.
After adjusting the scope, I chronographed the 35.3 gr. load with the bullets lightly into the lands. The velocity was 3003fps with a SD of 12. Stepping up to the 35.7 gr. load, the Berger bullets tripped the screens at an average of 3025 with a SD of 6. I did not seek any more speed, so I did not try 36 grains. I took down the chronograph and put up some wind flags. I shot several 3-shot groups that averaged about 3/8ths inch. None of the groups fired with the bullets seated into the lands matched the first group that had them off the lands.
In my opinion Hodgdon has a real winner with this new powder. It is very versatile as shown by my tests in three different cartridges and four different barrels. In the 6XC it will not match the velocity of Reloder 17, but it seems to be more accurate. In the 6mm Dasher, it not only has superb velocity but has excellent accuracy. Its real niche seems to be the 6 PPC. Although one must use more of it than N 133 or T-32, it will give super accuracy at most of its velocity range.
One may ask, ďAre you going to buy some?Ē
The answer to the above question is yes. I have already ordered a case of four 8# jugs from my local supplier.
1) Hodgdon Powder Co.
6231 Robinson Rd.
Shawnee Mission, KS 66202
2) Bartlein Barrels
W208N16939 N. Center St.
Jackson, WI 53076
3) Krieger Barrels
2024 Mayfield Rd.
Richfield, WI 53076
4) Bartís Bullets
821 Phelps Johnson Rd.
Leitchfield, KY 42754
5) Bishop Bullets
116 Toutle Park Rd.
Castle Rock, WA 98611-9629
6) Berger Bullets
May be purchased through your
Join the discussion of this article HERE at the Article Discussion Forum.
<Previous | Home
All times are GMT -5. The time now is 11:35 PM.