Simple Crossbow Mods for Improved Performance and Safety

A crossbow is not entirely a bow nor is it a rifle, though it does have elements in common with both. Like a rifle, the crossbow has a stock, a scope sight, a safety, and a trigger, and is fired from the shoulder. The recent surge in popularity of the crossbow provides some new opportunities for the gunsmith. And while some of the better models are superbly designed and built, there are still practical measures than can be taken to improve safety, ease of use, performance, and accuracy.

One thing that sets a fine rifle apart is its high-quality trigger. Similarly, work performed on a crossbow trigger mechanism can significantly improve its overall function. In this article I’ll detail one such recent project. The trigger on this crossbow had a very hard pull at 7 pounds 11 ounces. The trigger was also positioned too far forward, making it awkward to reach while holding the pistol grip. Many crossbows share the problem of a very hard trigger pull.

In a series of crossbow triggers I tested, the trigger pulls ranged from just under 2-1/2 pounds to nearly 9 pounds, with most around 8 pounds, which seriously compromises its potential for precision shooting. Typically, the crossbow has a trigger/sear mechanism that’s very similar to a rifle, but is essentially nonadjustable. The major difference lies in the cocked and loaded string latch (sear).

The Horton crossbow used in this article has a bow draw weight of 175 pounds, producing well in excess of 100 pounds of pressure on the cocking mechanism by the bowstring and resulting in a trigger and sear break that requires a very hard pull. As I mentioned, the trigger was also located far forward of the pistol grip, making it very awkward to reach and pull while aiming and firing.

The solution I came up with to solve both problems was to install a secondary trigger midway between the existing trigger and the pistol grip. The secondary trigger is linked to the existing front trigger, providing a variable geared-down pull ratio, depending on the link position used on the secondary trigger. The resulting trigger travel on the secondary trigger is proportionally greater, of course, but The new trigger (silver in color) is installed directly behind the original trigger (black).

Note how far forward the original trigger is positioned, making it almost impossible to reach. its movement is very smooth and positive. The operation of the crossbow’s safety is not affected in any way by installation of the second trigger. As the photos show, the major trigger parts were made of cast aluminum. The link between triggers is made of 0.095-inch-diameter steel rod

From the left are the triggerguard, trigger shoe with attaching hole and three holes for link adjustment, the connecting link, the milled base for trigger attachment (with screws), and the walnut pistolgrip extension cap. stock and is retained with #4-40 nuts at the threaded tips. The base of the trigger is attached to the frame of the crossbow with three #6-32 countersunk socket-head screws.

Making and Installing The Trigger Parts The trigger attaching base was made to size from 1/4-inch-thick aluminum plate with a slot milled to retain the pivotal end of the trigger. A #4-40 screw is used to attach the trigger to the base. The trigger shoe is also cut from 1/4-inch aluminum plate, shaped with a curve to fit the finger. The three linkage-adjustment holes in the trigger are spaced 1/4 inch apart, beginning 3/8 inch from the trigger-attachment hole.

The trigger link, which joins the two triggers, is 1.45 inches long. The very short pistol grip, the excessive length between the grip and the trigger, and the lack of a triggerguard are all puzzling features of this crossbow. The secondary trigger is linked to the original trigger, providing the necessary mechanical advantage as well as better ergonomics. The trigger guard and addition to the buttstock further enhance safety and practicality.

I made a steel tip and attached it to the tip of the original trigger with J-B Cold Weld. This tip has a hole in it for the trigger link. The tip connection serves to lengthen the original trigger by about 3/16 inch, thus providing some additional leverage to the system. The photos show how the whole system is put together. Actually, the original trigger is undisturbed by the connecting link at the tip and can still be used, assuming the shooter has a sufficiently long trigger finger.

For other crossbow models, there is some leeway in making the trigger system to fit while staying with the basic concept described here. Other Improvements I’m not sure why, but several crossbows from various manufacturers do not have the sort of trigger guard commonly found on a firearm, and their triggers are quite unprotected as a result. I chose to add a trigger guard to this crossbow. It was shaped from 1/ 8 x 3/8 inch steel, and is large enough for a gloved finger to enter the loop.

The trigger guard is attached with two #10-24 socket-head screws onto the forward part of the pistol grip and to the frame at the front. It provides the needed protection for the triggers. I also added a 3/4-inch-thick pistolgrip cap made of walnut. It’s attached with four #10-24 flat-head screws.

Above left and The new trigger is much easier to reach (right) while comfortably holding the lengthened pistol grip. The link between the triggers is in the center position, reducing the pull weight from 7 pounds 11 ounces to 2 pounds 8 ounces. This cap or extension provides a better grasp of the pistol grip during shooting, as well as enhancing the appearance of the crossbow. Conclusions I used a Lyman digital trigger-pull gauge to test the crossbow’s trigger after the modification.

With the adjoining trigger link installed in the upper hole, duced from pound 10 ors at the central hole resulted in a pull weight of 2 pounds 8 ounces. The lower link hole resulted in a 3 pound 5 ounce let off. This, I believe, provides a nice range of adjustments. The trigger pull was very smooth and uniform with the new system.

Reach with the finger to the secondary trigger from the rear of the pistol grip was changed from a nearly unworkable 4 inches to a comfortable 2- 3/4 inches, with room for the three lower fingers surrounding the lengthened pistol grip. erting the crossbow trigger in corrected two problems, king it much easier to shoot. Plus, the trigger guard makes it safer to handle. The cost of the materials was minimal, with my time being the only real expenditure.

All in all, I thought this was a worthwhile project, especially since it has brought a whole new clientele into my shop. I