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6.5-284
on a BAT Model MB Action Long Range Target Rifle
Completed 7/10/08
This rifle project
was conceived right after the 2007 F-Class national
Championships in September, 2007. After the 2007 competition
season, I had come to the conclusion that the MAK TubeGun, while
an excellent shooting rifle, was not optimum for prone F-Class
use. I had also found that the
LowRider stock on the 6 Dasher was a near perfect fit for me
and provided a very stable and repeatable platform for precision
shooting from the prone position.
I therefore decided
to build a 6.5-284 on a LowRider stock, and chose a
BAT model MB action as
the heart of the new rifle. I ordered a 1.250" OD Broughton 5C
barrel to complete the main suite of components. The build up
started during April of 2008.
The specifications
are as follows:
|
Caliber |
6.5-284
Lapua Match |
|
Barrel |
Broughton
5C, 1:8 twist, stainless, 31.5" finished length, contour
1.250" straight cylinder |
|
Reamer |
Dave Kiff of
Pacific Tool and Gauge – 6.5 X
284 Lapua Match, 0.297 neck, 0.120 freebore |
|
Receiver |
BAT Model MB
MultiFlat. This action has an extra 1" of action
extending past the barrel to action shoulder to provide
additional bedding area for long heavy barrels. |
|
Sight Rail |
BAT 20 MOA |
|
Trigger |
Jewel HVR |
| Stock |
West Custom
Rifles Lowrider in Black
Rutland laminate, with polished BAT triggerguard. Stock
has a Limbsaver pad. Pillars are stainless, made by me
for this action and stock. Greg supplied me with a polished escutcheon
for the front action screw. It is finished with
WaterLox Original
Sealer and Finish. The
barrel action is bedded with Devcon 10110 epoxy. |
|
Scope |
Nightforce NXS 12-42X56 with
NP-1RR reticle |
|
Rings |
Leupold QRW high, 30MM |
| Weight |
20.5
pounds. I may add 1.0 pounds to the buttstock after
testing it for a while. |
Break-in
showed real promise, with a couple 5 shot groups under
0.5" at 200 yards using left over TubeGun ammo.
7/13/08
Testing some
standard accuracy loads for my other 6.5-284 today, it was very
obvious that the rifle shoots very well indeed. Three loads were
tried, from the standard F-Class prone position:
Moly
142 grain Sierra MatchKing, seated 0.010" back from a hard
jam, 49.5 grains H4350, GM215M primer, Lapua brass
Moly
140 grain Berger VLD, seated 0.020" past the hard jam (bolt
seats the bullet when chambering), 49.5 grains H4350, GM215M
primer, Lapua brass
Moly
130 grain Berger VLD, seated 0.020" past the hard jam (bolt
seats the bullet when chambering), 51.5 grains H4350, GM215M
primer, Lapua brass
Conditions
were not great - switching fishtail wind at about 5 MPH, and a
ton of mirage in the prone position. I couldn't even see all the
bullet holes with my Alpen 88mm spotting scope. I also observed
at least 1 MOA point of impact variation over a few minutes from
the mirage. Shooting fast groups to try and get five off in a
constant condition, I was able to get a couple 0.7" groups, but
some were over 1.25".
I moved off
the concrete and sent to a shooting bench, and got rid of a
large portion of the mirage. The groups tightened up
considerably. All these loads were shooting about 0.5" to 0.7"
at 200 yards. The edge went to the 130 Berger load, which was
also my best load in the TubeGun. I will be doing a formal
re-tuning of this load for the new barrel, and will post
chronograph and on-target results.
You can see
that the crown is cut square and true from the perfectly
symmetrical "star" formed from combustion by products on the 11
degree target crown:
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