Thursday, June 21, 2012

1000 Yard front sight base and rifle Update

I shot the Bob Wright memorial 1000 yard match with my new 6.5/06 rifle last weekend, 3-20 shot matches and I put about 84 rounds downrange using unlimited sighters in the 1st and 3rd matches, had some issues getting on target to start with. The front sight base worked very well. didn't budge, did not get loose, nothing! stayed right where it needed to be.

Being that this is the 1st time I've had to fuss with getting MY OWN rifle on at 1000 yards with iron sights I had made a thermometer target and shot it at 100 yards to zero. The only issue I think I ran into however is my home range shoots a bit downhill and Camp Perry is near level I think. Everybody said I needed to zero 27 MOA high to be on at 1000. Later on the ballistics program I ran some numbers on after finally getting the chrono to catch the bullet and not the bits of grass or my muzzle blast said 32 MOA was what I needed.....The ballistics program was correct and when I came off the line having just finished with a pair of X's I had exactly 32 minutes on my rifle (128 Clicks). But when I shot on my home range to confirm this I was still only 27 MOA high?  and the two shots I fired at the thermometer target were touching and 7 inches out to the right (that was my wind correction from the last match and I hadn't returned it back to mechanical until I shot on the thermometer target) So I'm still doing a little head scratching there.   Soooooo I'm not really sure where my 5 MOA went to at this point in time, May re-fire the target again and see if I was just holding different that day. I hung the target with a plumb bob so that wasn't the issue....only other thing I could think of is the cold bore shots vs very hot bore shots....but 5 MOA???  the aiming black is 4.4" at 100 and 44" at 1000...hmmmm

Anyways my scores were pretty good I shot a 188-3X, 182-2X and a 176-1X I had some position problems and stock/cheek weld problems which resulted in a nasty abrasion on my cheek.

Monday, June 11, 2012

Shop project: Front sight riser/base for new 1000 yard rifle

With the help of my gunsmith mentor I've been putting a 6.5/06 rifle together for 1000 yard matches. This rifle is going to be using iron sights and shot all prone. The issue here is that the rear sight mount on this rifle puts the rear sight nearly 1 5/8" above the center line of the bore. The barrel which started out life as a 1.25"x28" blank is now a tapered barrel going down to .850" at the muzzle. The Redfield sights that I am using should parallel with the barrel so I can zero and practice at 200 yards and move out to 1000 yards easily, right now the rifle would shoot about 20' high at 200 yards if the front sight was mounted so low. So I need a front sight base that raises the front globe up about 1/2" roughly or so. Did I mention the first match I plan to shoot the rifle in is in a week? I've only had the action for a month so its been a bit of a race to get everything together. Sadly my mentor is very busy this month so I'm on my own to make a front sight base for this rifle. I'm choosing to make a single piece clamp style out of 6061 Aluminum. Its simple lightweight and pretty straight forward to make.

Note: I used a webcam for the pictures, did not have a camera to use while I was making chips sorry.

The design is a one piece clamp style.
Attempt #1 ended in a off center hole, Yes I could have machined material off the large side but  I chose to just try again, I can always rework the 1st piece.

Muzzle view of the new riser/mount, for a first completed attempt I'm pleased, I could probably remove 1/2-2/3rds of the material and still have a strong base. If I would do that I would get rid of the bottom portion the screws go through and make recessed slots in the body of the riser. Then reduce thickness in the sides and drill some 3/8"  or 1/2" holes in the sides and obliques.

From the front it looks pretty crude...I think it was just the angle, the side view looks a lot better in
my opinion and shows just how bulky it is. Like I said 1st attempt, very utilitarian, may make some modifications with it....then again if it works I may just leave it.