Loose screws / Changing POI

[Kegbelly]

Kb, when you pull those OEM screws out, do me a favor and measure their exact length with a set of calipers.

I see other forum threads here where people used screws that were 5/16" long. I believe they said the two in the back could be 3/8" but the two in the front had to be cut down to 5/16". The 1/8" difference between 1/4" and 3/8" is a big difference for something like this.

Significent, I came up with .290 on the threads but I think Norm's measurements are correct. My screw heads stripped when I tried to remove them, had to drive a 1/4" drive T-15 Torx bit into each screw head to remove them, so the heads are boogered up. Not a pleasant feeling hammering on your crossbow
Anyhow, I went to Fastenal and got SKU # 23128, these are Holo-Krome 8-32 x 5/16 socket cap screws. You could use longer screws on the rear 2 screws but anything longer than 5/16 on the front two screws will bottom out on the trigger claws and interfere with their movement.
So I'm back together now and hopefully have the loose screw issue fixed once and for all... The allen head on the factory screws had rounded out to the point where I couldnt get them tight enough, after a few shots they worked loose again.
So I wanted to post this in hopes that it might help someone out and save them some headache
EDIT... forgot to mention I also bought Fastenal SKU 1123112 which is the same screw in 1/4" length just in case the 5/16 was too long.

[Significent]

Kb, good to know. Thanks for the follow-up. Are the heads big enough? They must be. Hopefully, I'll never need them, but if I do, I know where to look.

[Kegbelly]

Yes, it takes a 9/64 allen, you can definitely get a good bite on these. The heads do stick out since it's a socket cap style screw but if they stay in place that's my first concern.

[flinthead]

Keg,

So you used the 8-32 5/16" screws front and rear with no problems??

[Deerstalker]

You want to check the length of the thread on the front 2 screws with one of the old screws that have been removed from the scope rail. This is to ensure that the front 2 screws DO NOT interfere with the 2 claws of the string latch. If these screws are too long they may bind the claws and stop the latching or unlatching of the string when cocking/firing. You DO NOT have to worry about the 2 rear screws which can be 5/16".

[Kegbelly]

Keg,

So you used the 8-32 5/16" screws front and rear with no problems??

Yes. I test fitted the 5/16" front screws before I loctited them in, used a pencil to lock the trigger claws back like when you cock it, and released the trigger several times to make sure the front screws didn't interfere with the trigger latches/claws.
On the rear screws, there's space inside the scope rail so you could even use 3/8 if you wanted to. It threads all the way through.
This picture is the 5/16" screw on the left, the factory screw in the middle, and the 1/4" on the right. I tried to line them up like how the head would butt up against the scope rail when tight to show the differences in thread length. The 5/16 is actually closer to the factory screw length than the 1/4", I count 8 threads on each, and 6 threads on the 1/4"