Homemade Crossbow Bore Sighter
Okay, I promised to tell you about how I saved money on a bore sighter that I could use on rifles (and handguns), as well as crossbows. Now, the first thing to remember is that, unless you can afford the bore sighters that the military uses, an inexpensive bore sighter will most likely NOT get you PRECISELY where you need to be. In other words, you’ll expect to make a few minor scope adjustments after you use the bore sighter.
I have a bad habit of misplacing my stuff from season to season, so this year I had to purchase a new bore sighter. Being extremely thrifty, I came up with a plan in my head. I had no idea if it would really work well, but I AM CHEAP!
Totally disregarding all of the customer ratings at all the familiar outdoor and hunting stores, I purchased a CenterPoint All-in-One Laser Bore Sighter from Walmart for $39.00. It will work with any caliber from a .177 to a .50, according to CenterPoint. I have scopes from this company that came with a couple of my nitro air rifles, and I’m pleased with them.
According to many of the ratings from previous buyers, a common complaint is that you cannot even push the arbor for the .177 into the barrel. I found this not to be a problem. I believe that what might be happening is that, as the user screws the arbor onto the end of the bore sighter “limb”, they might go beyond actually attaching the arbor and, perhaps, begin to “fatten” the arbor beyond its ability to enter the barrel. Mine worked well with all my .177 caliber rifles. The Nitro Venom was actually “spot on”, without further adjustment at 30 yards.
Some users had problems with the batteries and the battery compartment. I guess I was just blessed, because I had no problem at all. I’ll admit, you DO have to be a bit delicate with the battery configuration and turning it on and off.
Okay, here’s how I adapted the same bore sighter for my crossbows. There are several crossbow laser bore sighters available. Some are screwed into the point end of the shaft just like a point. One model is actually made just like a bolt. You twist the “nock” to turn the laser on and the beam comes out of the “point” of the arrow. Cool, but I’m Mr. Cheapo, like I said!
First, I needed a way to align the laser sighter with the bolt channel on the crossbow. What better way than with a nice straight bolt? I have purchased many of the aluminum 2219 target bolts that you can get from the Japanese suppliers on Ebay. All you need is a nice straight piece that’s long enough to extend from where your string rests on the barrel to a few inches beyond the end of the barrel – just like a broadhead might rest. For me, it just took about six inches of the nock end of a bolt.
Now, this is where you’ll want to take your time. You’ll need to cut the bolt with a nice square and clean cut. Then, you’ll want to deburr the cut end of the bolt so that you won’t abraid the bevel of the bore sighter, as you twist it into place into the shortened bolt. I personally used a chain saw blade file and lovingly put a 45 degree bevel on the inside lip of the cut end.
A 2219 bolt has an inner diameter of .305″. This bore sighter kit comes with one arbor for .270 to .320 cal barrels. You insert the bore sighter into the open end of the short bolt using this arbor and you’re in business! Now you have a short bolt with the laser sighter loaded. Place the bolt into the end of the crossbow and “anchor” it into the barrel channel by simply setting it under the un-cocked bow string. Test the sighter end of the bolt to make sure there’s no play. Now clamp that crossbow down (if you haven’t already) and tune your scope in the same way as you would a rifle. I also adjusted the iron sights on the crossbow while it was secured.
I plan to make a video of this process – it’s just that I started late today. When I get it done, I’ll throw it up here.
Remember – don’t expect a laser bore sighter to do the whole job, even though you might get lucky once in a while. It’ll get you on the paper so you can tune it in without expending quite as much expensive ammo.