M305 break in

Does anyone break in the barrels on these and if so whats your procedure

As you can perhaps tell, barrel break-in is a controversial subject....

For the stock M305, clean it thoroughly, lube the action [lots of info in the stickies] and shoot it lots. The barrels on these rifles are generally pretty good, but you are unlikely to get match grade accuracy no matter what you do to them.

If you have a match barrel... The theory is that carefully and thoroughly cleaning the barrel after firing a couple of rounds and letting the barrel cool will remove any microscopic burrs or rough spots in the rifling cuts. Essentially, you're using jacketed bullets to polish the bore. However the M14 platform simply isn't going to get you the kind of accuracy where this procedure makes a difference. Do it if you want, but [IMHO] your time will be better spent doing the various well-known tweaks for the M305...tightening up the gas system and recoil spring assembly, replacing a few parts and lapping the bolt lugs and developing handloads for top performance. However what this will generally accomplish in the large majority of cases [based on my obsessive reading on this forum] is that you _may_ turn a 3-4 MOA gun into a 2-3 MOA gun...unless you are one of the lucky few that gets a good functioning, exceptionally accurate rifle right out of the box.

In my view, this is a battle rifle that is to be shot for fun, and minute-of-zombie accuracy is enough.
 
I just follow the same break in procedure with all my guns. Some guns you will actually notice the groups get better as the barrel breaks in. Not 100% sure if its the gun or the user getting use to the rifle.

1st - I clean the barrel before shooting. I don't over clean it. Just one pass with a brush, and one pass with a patch. Then off to the range. Bring your cleaning kit with you.

2nd - I fire a single shot at a target I place at 25 or 50 meters. After the single shot, I clean the barrel. One pass with a solvent patch, dry patch, then lightly oiled patch. Repeat this 3 times.

3rd - I fire a 3 shot group at 50 meters. Each shot is a minute apart. Clean the barrel after the 3 shots. Same cleaning procedure as step 2. Repeat 3 times.

4th - I fire a 5 shot group at 50 meters. Each shot is a minute apart. Clean barrel after the 5 shots. Same cleaning procedure as step 2. Only do this once.

5th - I fire my last 3 shots at a target 100 meters trying to achieve the best group possible and record the group. Keep it actually.

After 1 box of ammo you should of removed almost all burrs in the barrel by then.

My CZ 550's groups are still tightening as I use it and its only over 50 rounds though it. When I first got it, it was 50mm (2") with a scope in a 3 shot triangle pattern. Now, in that same triangle pattern, the group has shrunk to 25mm (1") with the occasional 20 - 22mm (3/4") 3 shot group. Still, I'm unsure if its the rifle or the user.
 
The chrome in these barrels is chrome plating..." usually" there is some kind of prep before the plating. Any imperfections not removed are "cast in stone" as it were.

The hard chrome plating will not be affected by a bullet or two unless you shoot abrasive bullets
 
From West Coast Armoury makers of match barrels.


If you are thinking about breaking in a chrome lined barrel - don't bother. There is no reason to break-in or polish a chrome lined barrel, the finish is very durable and any imperfections are now part of the hard chrome surface.
 
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