Another great tutorial from Robert(gubb33ps) on crowning barrels

Here's a REALLY handy tutorial from Robert(gubb33ps) on basic barrel re-crowning. This question gets asked a lot by modders, so here is some very good information on how to perform this mod. Thanks again Robert!


MODIFICATION 2: Crown

This adds on to the last post (which added on to the first post).
http://www.network54.com/Forum/275684/message/1296439674/2260+basic+trigger

(Yes, do have a lathe and normally recrown with one. But for this, will recrown the simplest way; one that the average guy may feel is easy enough that they will attempt it. The good news is that no matter how you foul up, can always trim ¼ inch off the barrel and try again.)

This gun actually shoots well as it is, but am going to recrown it as a tutorial anyway (and if it shoots a little better, will count it as a bonus).

1.Get the front sight off. It is a plastic part, held on by just being a press-fit.
2.A block of wood makes the best removal tool. Ju8st make sure it is clean, slide it along the barrel, and smack the front sight.

3.The sight will pop off. Pick it up (undamaged) as I intend to reattach it after recrowning.

4.Notice how the barrel has a flat spot. The sight has a spot inside that matches that flat spot, so you'll be able to put it back on straight.
5.This is what the factory crown looked like. Pretty ugly, but the results of the previous tests weren't bad at all. Pretty is as pretty does, and even as ugly as this crown is, it shot pretty well.

6.Chuck a round headed BRASS screw into an electric drill.

7.Coat the brass screw with an abrasive compound. Can use automotive rubbing compound (not polish, the more abrasive rubbing compound for well oxidized paint), valve grinding compound, even COMET cleanser will work for this. I used a fine abrasive compound made for air bursh use when etching glass mixed with lithium grease because that is what I had.
8.Place the screwhead into the muzzle, run the drill at medium speed, and rotate the drill around in a figure 8 pattern.(understand, the screw head stays in contact with the bore, you pivot the drill around in that 8 pattern.)

9.Take a look every minute or so. Are not trying to remake the whole end of the barrel, just the edge of the bore. Even, smooth, and polished are the key words. This was done in about 90 seconds of polishing.

10.Clean the barrel.
11.Reattach the front sight. All I did was add a drop of glue and tap it back on with the same wooden block that was used to take it off.

TESTING:

Charged the rifle and fired 3 5-shot groups using the same H-point pellets used in the last test.

5-shot groups
20yards
Issue 'peepsights


Cannot honestly say it is definitively better, but it started out petty good. Can say it is not any worse, and is likely to test out to be better, but it will take more shooting to be definitive.

Someday, will put that steel breech on the gun,s cope it, and see what it can do. But for now, it is much better than I expected it to be and it is kind of fun having a 2260 that looks pure stock but shoots this well.

Other than the time to do the two mods, the only $ expended was $5 for a 4-40 tap (used in the trigger mod). Brings the cost up to $89 and about 90 mins. of my spare time.

Robert's(gubb33ps) excellent 2260 trigger tutorial

With Robert's(gubb33ps) permission, I want to post his trigger tutorial from the green right here on the blog so more people will get to see it. This is extremely useful if you have a new 2260/Discovery and want to get the trigger pull down to a nice crisp 2 stage feel. Follow this tutorial and you will give your gun a sweet trigger in no time for just pennies. Thanks Robert!


Dovetailing into this post:
http://www.network54.com/Forum/275684/message/1296340399/Back+to+Basics+%282260%29

Are several ways to do the trigger of a 2260 (or a Discovery as they use the same trigger system), but this way is simple enough not to scare off a new shooter. May be a bit more detailed that really needed, but am trying to avoid any surprises.

FIRST MODIFICATION: Trigger Job

A simple 2-screw trigger mod should be pretty easy for the average guy. Once you have the tools laid out, it will take 30 min to do.

You are going to need the following:

1.A thin sharp pointed instrument (like an awl, but a heavy needle or thin nail will do).
2. Phillips screw driver to fit the stock screw.
3.Small slot screw driver to fit the trigger unit side plate.
4.4-40 tap (the drill and tap set is in a blister pack at HomeDepot for about $5-$6).
5.two 4-40 1 screws and nuts to fit
6.Something to shorten the 1 long 4-40 screws ( a Dremel tool, bench grinder, or even a hack saw and a file will do the trick just fine).

The reason for a 4-40 2-screw trigger job rather than a 3-screw is simple: the factory already drilled the two holes you need and the two holes are already the right size for a 4-40 tap. If you want to use larger 6-32 screws, are going to have to drill those holes slightly and use a 6-32 tap (buy a tap and drill bit together, they are sold in blister packs at Home Depot).

STEP 1: Get the rifle out of the stock.

The safety sticks out too far to allow you to take the metal work out of the stock. That safety runs on the tail end of a rat trap type spring.

You can see the tail end here:


1.Flip the rifle so the SMALL DIAMETER of the safety is ON TOP.

2.Use your awl (or thin nail) to pick up and slightly lift the tail end of that spring.
3.Safety button will fall out the other side.


With the safety out, can remove the phillips stock screw, and lift the metal work out of the stock.

Take a look around the trigger. On the back of the trigger housing there are already two (empty) holes in the plastic housing. Eventually, we're going to run a 4-40 tap into those holes and fit screws.


On one side, there is a side plate with two screws holding it on.

4.Take out the two screws and remove the cover plate.

5.Take a look at the trigger parts to remember where they all go. At this point, will usually take out my cell phone and snap a picture so I will be sure to get it back together right.

6.Remove the trigger parts leaving the trigger housing empty.

7.The holes in the back of the trigger unit are just about right for a 4-40 tap as they are, you won't need to drill them.

8.Fit the screws (with nuts already spun on) into the holes. Let them hang out, just putting them in right now so they won't get lost.

9.At this point, will grease the pivot holes and the pivot pins with white lithium grease. Can use any good grease, but as it is a plastic housing, tend to go with qa plastic safe grease.


Put all the parts of the trigger back in and put the side plate back on. It has to mate with the up ends of the 3 pivot pins and will just snap down once they line up.



Some people substitute a lighter weight trigger spring. I elected NOT to, but if you have the urge feel free to indulge.

ADJUSTING AND SHORTENING THE SCREWS:

10.You have to put the safety button back in even when the gun is out of the stock. The tail end of that spring runs the safety, but the top end runs the sear. Without the safety, there is no spring pressure on the sear, and the gun will not cock, so the safety has to go back in. The bottom screw limits how far back the trigger can pivot (backlash or over travel). The top screw limits the sear engagement. Start with the bottom screw.
11.Cock the gun and run the bottom screw in until you feel some resistance. Pull the trigger and it will not move enough to fire. Keep backing out the bottom screw while you pull the trigger until the trigger lets the sear trip and the gun fire.


12.Measure how much screw is between the nut and the screw head. This is how much you have to shorten the screw.

13.You really do not want the screw to be dead flush, will want to have a little adjustment in just in case things change over time, so do NOT shorten the screw the full amount. Subtract 1/10 or so to allow for some more in adjustment later on. I will measure, then color the end of the screw that has to be removed with a Marks-a-Lot. Make the end of the screw as flat and polished as you can.


14.The top screw sets the sear engagement. Cock the rifle and start slowly turning that screw in. At some point, the rifle will fire.
15.Back the screw out 2 full turns and try the trigger pull (two turns of a 4-40 screw would be 2/40 of an inch, or about 1/20 of an inch).

16.Shorten that screw just like you did in steps #12 and #13.

17.Take the safety back out.
18.Put the metal work back in the stock.
19.Put the safety back in.
20.Test the trigger pull. A good test to bounce the rifle on a carpeted floor a few times to see if it will fire.
21.Test the safety. Put the gun on safe, pull the trigger. If it fires, it fails. If after you've pull the trigger with the safety on, it fires when the saftey is clicked off, it fails.

Can fiddle around with the screws a fraction of a turn at a time, but do not expect a SAFE pull at much less than 1 pound. Will be a crisp little movement pull.


With some fiddling around and adjusting, the above trigger came out at 1.1 pound, no creep, and very little over travel.

So I had to test the difference a better trigger pull made, at least to the best of my peep sight ability.

The better choices from yesterday's test were retested today. Perhaps the better trigger pull really is the best accuracy mod.

Three 5-shot groups for each pellet.
30 shots on one 12gr.
(green construction paper used as a backer to better show holes for the photograph).