April 29th, 2007

Field Report–Reloader 15 and new Berger 105s in Donovan's Dasher

Forum regular Donovan has recently been testing the new-generation Berger 105s in his 6mm Dasher, using Alliant Reloader 15 powder. He reports: “They are shooting better then the old ones did in this barrel for me. Beside the accuracy I am getting from the new Bergers (6″ groups at 1000), they are very uniform and I see no need to segregate them. I measured around 70 by base to ogive and by OAL and stopped there.”

In the course of his testing, Donovan used two different lots of RL15, one purchased this year and one from 2004. He was pleased to report both lots performed almost identically, giving excellent accuracy and velocity:

Lot # 45144 (November 2004)
Velocity Average = 3119 fps (10 shots)
Pressure Average = 61,348 psi
Elevation to 1000 yards = 23.6 MOA
Group at 1000 yards = 5.9″ (5-shots)

Lot # 65006 (March 2007)
Velocity Average = 3121 fps (10 shots)
Pressure Average = 60,977 psi
Elevation to 1000yrd = 23.5 MOA
Group at 1000yrds = 6.1″ (5-shots)

6mm Dasher 1000 yards Donovan Moran

Donovan was shooting a 28″ 8-Twist Shilen, 105 Berger VLDs (Lot #0559), with a 32.0+ grain load of RL15. (Donovan notes his barrel is pretty fast so other Dasher shooters may need more powder to reach the same velocities.) Temperature was at 84° F, and altitude 1325 feet. Pressures were measured with an RSI Pressure Trace, and velocities were recorded with a CED Millennium chrono set up with 8-foot spacing and infrared lighting. Donovan has also been comparison testing the 115 DTAC vs. the new 117gr Tubb bullet. We hope to have a complete report on those results in May.

Regarding the 115s, Donovan had this interesting gunsmithing note: “I have an older Shilen barrel that had a .104″ throat up until last December. I had been using it for 105 types mainly. It had always shot Berger 105-VLDs about the best, then AMaxs, followed by 107gr SMKs and then 105gr Lapuas. I had even tried the 115 DTACs with it a few times, but it shot them marginal to say the best. Then I felt the accuracy had diminished somewhat and it had near 1200 rounds down it, so I decided to re-crown it and throat it longer to get past some of the erosion. I pushed out the throat to .165″. Interestingly, in December this re-throated Shilen shot the 115s best followed by 107 SMKs and then the older lot of Berger 105s. At 1000 yards, two 5-shot groups of 115s both went under five inches.” What’s the lesson? Don’t toss that old barrel–you might find it shoots great with a fresh crown and new throat.

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