Some of the simplest features bring the greatest benefits. Take for example the D-loop or Nock or String loop on a bowstring. I have been utilizing this little gadget for, heck I don't even remember, but I know it has been at least nine years if not more.
When I first heard about the D-loop I was a little skeptical. I thought my brass knock was more than sufficient. A little while later while practicing I had an arrow fall off my string when relaxing from full draw. Now this quickly brought to mind a hunting occasion where this same situation cost me a shot at a whitetail. This event immediately got me thinking about the D-loop again.
It was however late in the year and I was looking forward to a new bow soon. On my next trip to the local pro shop I spoke with the manager about the D-loop. He informed me that he had been shooting one for a while and I decided to give it a try on my new bow setup. All I can say is that I have never looked back because the benefits (pros) heavily outweigh the cons.
I am going to go through the steps I recommend to place a D-loop on your bow string. These steps go through the process as if your bow is new. If you are adding a D-loop to your existing setup then skim over the first couple following paragraphs.
I recommend a BCY Polyester string material which is 2.00 mm in diameter, four and a quarter to four and a half inches long. (insert file)
After the material is cut to length, first use your fingertip to fray one end of the string by pushing the fibers apart. Once separated use a lighter to melt the end you just frayed.
It shouldn't take very long once lit to form a small melted ball twice the size of the string. Blow out the flame and the small ball will immediately harden. Now do the same to the other end of the string. I recommend the ball size being at least twice the size of the string and I will explain why this is a very important part later.
New Bow Preparation
Next make sure that your arrow is level on the string to start with. Later you can tune your bow rest but starting out level is the best measurement. To do this I recommend two level types, string and arrow, that are inexpensive and you can pick up from your local pro shop in addition to a bow vise. First place the bow in the vise and use the string level against the bow string to check for vertical level. Once level position the arrow on the string and place the arrow level on the arrow. Adjust the nock of the arrow on the bowstring until the level reads horizontal. Once level mark the bowstring on the top and bottom of the nock.
Now this is where we actually begin to tie the D-loop on the string. If you are replacing your brass nock, go ahead and remove it.
I like to start off by connecting the top part of the D-loop. Take the D-loop string and place it on the left side of the bow string with about a half inch of the material pointing towards the back of the bowstring.
Wrap it around the front of the bowstring and bring it back around over itself.
Now wrap it around the bowstring again and back through the loop you just made.
You can now snug the material up against the string by pulling on the longer end.
The small ball you made earlier will keep the material from pulling through the loop.
At this moment you will want to double check the level of the arrow. Place the arrow back on the bow with the first D-loop knot above the nock. If you need to make any adjustments the upper knot you just tied should be able to travel up and down the string. If it is too tight just loosen the knot, adjust and then retighten. Remove the arrow.
Now you are ready to make the bottom tie of the loop. Start with the string material and place it on the right side of the bowstring.
Next wrap it around the right side of the bowstring and then come back around above the D-loop string and through the loop you just made.
Next bring the string down and then loop it back around the bowstring on the left hand side.
When you do this you form a tiny loop
that you can push the beaded end through.
Pull on the D-loop in order to snug it up. Now you can make adjustments to make sure the loop lines up with your arrow. To tighten and finish up the D-loop I recommend attaching your release on the D-loop and pull while placing the fingers of your other hand above and below the newly tied knots.
The D-loop is now complete.
The D, or String Loop Ready to shoot.
I want to explain the importance of the melted string ends being at least twice the diameter of the string. This will keep the knot from untying when drawing the bow. I know of a couple people, yours truly included, who have given themselves a fat lip when one of the knots have come untied. If you follow the diameter recommendation you will never have to worry about the D-loop coming untied. The only other con I can think of from this setup is you may loose up to ½" of draw length. This is quickly overcome due to the accuracy that most pick up from the D-loop enhancement.
What other benefits come from a D-loop. Well for starters you no longer have to worry about your arrow coming off the string when let down. String wear is virtually eliminated because your release is no longer attached directly to the string. The amount of time between changing a string is greatly increased; instead just change the D-loop. I find my D-loops have no problem lasting me an entire deer season. I would say with the addition of a D-loop you can double the life of your bowstring.
Continuing with the benefits, arrow pinch between your release and brass nock is now eliminated as with the D-loop equal pressure is applied above and below on the bowstring. The angle of the string is eliminated, now your arrow will no longer be forced partially out of the nock. Also when using a brass nock hooking the release under the arrow will tend to push the brass nock up thereby changing your arrow nock point. This can also cause your arrow to push down on the rest at full draw, sometimes even enough to flex the shaft. These problems with a brass nock are intensified as draw length increases or axle to axle length decreases.
The best improvement I remember when switching to a D-loop was that my group sizes shrank and were much more consistent. This was especially true when I got use to the new setup with my old release. The way it hooked onto the string was a little more difficult since the D-Loop was not tight or firm like the bowstring with tension. It took some practice but I did overcome it in a short amount of time. I have since switched to a different release but still use my old one as a backup. My new release has a more distinguished hook that is not as recessed as my old release. You will also find that most releases are designed with a D-loop in mind, shorter barrels or bodies, triggers closer to the caliper(s) to increase draw length.
You will also find most if not all Pro Shooters utilizing a D-loop as the benefits far and away outweigh the consequences.
A final point I would like to point out about the D-loop. It is very inexpensive to make and even easier to put on and take off. So after the season is over I suggest you outfit your bow with one of the simplest items that will enhance your accuracy, a D-loop.