Boresighting Woes

[boricua9mm]

After several years, I decided to put a new scope on an ooooold Marlin model 25. My father bought the gun used at a pawn shop for $40 over 15 years ago. I stripped and refinished the ugly wood stock back when I was in college. I recently bought a Simmons Master Series Prohunter 3-9x 40 forf the little rimfire tack driver. I know, I know, not the best scope, but I really didn't want to put $300 worth of glass on a $40 pawn shop gun!

I mounted the scope with some Leupold rimfire rings, leveled the cross hairs, and went to boresight the gun. I was using a BSA boresighter. Once I set the arbor into the barrel, the thing flopped left and right, and wasn't tight at all! There was no way I would have been able to bore sight it with it being so loose.

The gun IS a real tackdriver at 50 yards, so I can't imagine that the barrel is shot out so much that the .22 cal arbor wouldn't fit in properly. I have a strong feeling that the .22 cal arbor from this set just isn't the right size, but I guess it's possible that the rifling is so worn that it just isn't keeping the boresighter steady! I'm wondering what some of you rifle afficionados think about this. Like I said, the gun holds incerdible groups. Is it possible that the gun could hold such tight groups with a barrel that's shot to hell? Conversely, is it more likely that the .22 cal arbor from the boresighting kit just isn't in spec?

Hmmmmm.....


B9

[MrJamesK]

It could be the rod with the sight tool.

I have had that happen before. I solved it by getting a weight and string. I hung the string from the bottom of the tension on the tool itself. This helped keep it level.

Give it a try. Good luck.

[farmer]

My guess is that its the tool. Rifles will not shoot well with a worn barrel. I am not sold on bore sighters. I've been an avid rifle shooter for years, and I've never used one. I Just start at 20 yards and work my way back, it only takes two shots at each range.

[boricua9mm]

Originally Posted by farmer

My guess is that its the tool. Rifles will not shoot well with a worn barrel. I am not sold on bore sighters. I've been an avid rifle shooter for years, and I've never used one. I Just start at 20 yards and work my way back, it only takes two shots at each range.

That's what I figured. I guess I just need to hit the range and do it the good ole' fashioned way. "Get on paper!"

[Mercmar]

It's not like you're going to go broke, getting on paper with a .22

[nightraider]

Wait, isnt the Model 25 a bolt action gun?

Sighting in a bolt action gun is EXTREMELY easy, just make sure you use sandbags as it stabilizes the gun very well. Just take out the bolt, look down the barrel and while looking down the barrel just move it on target, dead on center.

Next keep the gun exactly in the position you had it in with the barrel lined up with the bulls-eye. Now carefully look through the scope without moving the gun and adjust the scopes crosshairs onto the bulls-eye.

Keep repeating the procedure until you have it close and then fine tune it through the scope when shooting.

[dstorm1911]

did ya ADJUST the arbor? the nylon end is adustable by tightening the small screw in the end to make it larger ya loosen the screw to reduce the diameter, I generally get it to slide in snug then turn slightly to actually lock the nylon end into the rifling.........

[boricua9mm]

Originally Posted by nightraider

Wait, isnt the Model 25 a bolt action gun?

Sighting in a bolt action gun is EXTREMELY easy, just make sure you use sandbags as it stabilizes the gun very well...

Make no mistake, I'm not needing help sighting in. The specific concerns were with the boresighting method.

Originally Posted by dstorm1911

did ya ADJUST the arbor? the nylon end is adustable by tightening the small screw in the end to make it larger ya loosen the screw to reduce the diameter, I generally get it to slide in snug then turn slightly to actually lock the nylon end into the rifling.........

The arbor in this kit is not adjustable at all. There are no nylon components of the arbors, only a brass hook pinned into place to lock into the rifling. Upon inspection, the hook on the .22LR arbor simply wasn't positioned properly. This results in the inability of the arbor to grab the rifling properly, making the boresight flop to either side with ease. No biggie, I'll be doing it the old way.

[one-eyed-fatman]

Originally Posted by nightraider

Wait, isnt the Model 25 a bolt action gun?

Sighting in a bolt action gun is EXTREMELY easy, just make sure you use sandbags as it stabilizes the gun very well. Just take out the bolt, look down the barrel and while looking down the barrel just move it on target, dead on center.

Next keep the gun exactly in the position you had it in with the barrel lined up with the bulls-eye. Now carefully look through the scope without moving the gun and adjust the scopes crosshairs onto the bulls-eye.

Keep repeating the procedure until you have it close and then fine tune it through the scope when shooting.

There's your answer.

[vafish]

Originally Posted by boricua9mm

Make no mistake, I'm not needing help sighting in. The specific concerns were with the boresighting method.

And nightraider explained the original bore sighting method. Look down the bore with your eye at a distant object, then holding the gun very steady alight the sights with the distant object.

It's all I've ever used on bolt action rifles.

I usually bore sight that way on my kitchen table aiming at some distant point out the window. Gets me close enough to be on the paper at 25 yards.