Pitted Crown Repair

Spannerman7

I read somewhere you should leave the moderator attached to the gun as often as possable, well I disagree, I am a stickler for cleaning and maintaining my guns. But with the T8 mod is very difficult to clean and dry out. This is what it was doing to my crown, it's on my 220 swift by the way.



I noticed my rounds were begining to drift around a bit, there is also slight pitting in the bore about 1" in, just on one land, I was tempted to crop back but did not after.
So what to do, I said if I'm doing this I may as well machine on an 11 deg crown, now with all things expensive to replace I made up a mock barrel in stainless to ensure the CNC program was correct, here is it after machining.



I decided I wanted a bit more protection for the crown so I modded the program slightly so the begining of the taper was recessed 1mm.
In the next closeup you can see there is still pitting on the first thread, it's fine as if I wanted to fix this I'd have to crop back at least 30mm.



So now a nice new clean crown, Oh yeah, I have a machine shop and about 20 yrs of engineering behind me, just incase you thought I tackled this with a tap and die set and a few files. The machining took about 10 mins, the setting up took about an hour and a half, no doubt the lads who do it for a trade have all the jigs already made up, I have no prob doing this for my own rifle but not in a million years would I touch anyone elses, each to their own job etc
No travelling and no cash spent ( I don't have any anyway) :rolleyes:

Just thought I'd share some rifle porn with ye
Spannerman

When will this stupid wind die down, I want to see what it's like, and this evening is out, NARGC Meeting

deerhunter1

Spannerman7 wrote: »

I read somewhere you should leave the moderator attached to the gun as often as possable, well I disagree, I am a stickler for cleaning and maintaining my guns. But with the T8 mod is very difficult to clean and dry out. This is what it was doing to my crown, it's on my 220 swift by the way.



I noticed my rounds were begining to drift around a bit, there is also slight pitting in the bore about 1" in, just on one land, I was tempted to crop back but did not after.
So what to do, I said if I'm doing this I may as well machine on an 11 deg crown, now with all things expensive to replace I made up a mock barrel in stainless to ensure the CNC program was correct, here is it after machining.



I decided I wanted a bit more protection for the crown so I modded the program slightly so the begining of the taper was recessed 1mm.
In the next closeup you can see there is still pitting on the first thread, it's fine as if I wanted to fix this I'd have to crop back at least 30mm.



So now a nice new clean crown, Oh yeah, I have a machine shop and about 20 yrs of engineering behind me, just incase you thought I tackled this with a tap and die set and a few files. The machining took about 10 mins, the setting up took about an hour and a half, no doubt the lads who do it for a trade have all the jigs already made up, I have no prob doing this for my own rifle but not in a million years would I touch anyone elses, each to their own job etc
No travelling and no cash spent ( I don't have any anyway) :rolleyes:

Just thought I'd share some rifle porn with ye
Spannerman

When will this stupid wind die down, I want to see what it's like, and this evening is out, NARGC Meeting

Nice job. I also dissagree with leaving the Mod on, manufacturers always reccommend taking it off when not in use. By leaving it on you get a build up of condensation inside the mod which tranfers to you weapon. My T8 gets a good cleaning with WD40 and a 12g cleaning brush is the perfect fit

dwighet

GOOD JOB SPANNER...
You`ll be making your own moderator and muzzle break soon...Bet you already have the drawings in progress;)

ATB
Dwighet

murph226

you mean the condensation transfers to your firearm DH1;)

Tackleberrywho

Interesting to see, do you think it was from scrubbing the carbon off the old crown that caused the trouble?

I have a theory that over cleaning can be as bad as no cleaning, I see it with machines in work that are cleaned so often that it causes wear for foreign particles to stick to, ref: Carbon etc.

Spannerman7

Hi Tack, I think it was a combination, the moisture from the mod being the main culprit, I'd swear it was the T8 manual that said to avoid excessive removal/replacement, I could be wrong however. I always store my firearms cleaned and just wipe a rifle bore dry before going shooting and this is the only one I ever had issue with.

Now, my next problem, how does one go about bluing the newely exposed steel, have any of ye lads done this, and keep it cheap

Tackleberrywho

Spannerman7 wrote: »

Hi Tack, I think it was a combination, the moisture from the mod being the main culprit, I'd swear it was the T8 manual that said to avoid excessive removal/replacement, I could be wrong however. I always store my firearms cleaned and just wipe a rifle bore dry before going shooting and this is the only one I ever had issue with.

Now, my next problem, how does one go about bluing the newely exposed steel, have any of ye lads done this, and keep it cheap

I used to use blackfast (TM) on steel, I used to bead blast the steel until it was raw, the dip it into this blackfast and it gave it a bluey black colour.

I would plug the barrel with wax or some material so the rifling was not contacted. Then I would dip, but i never did it on a rifle.
I would use the cleaning rod to remove the plug material post!! We would not want a bulged barrel later

I have seen blueing for sale in a few gunshops, not sure of the quality. Wash the barrel with IPA or Ether Alcahol so it goes on evenly

Tackleberrywho

Spannerman7 wrote: »

Hi Tack, I think it was a combination, the moisture from the mod being the main culprit, I'd swear it was the T8 manual that said to avoid excessive removal/replacement, I could be wrong however. I always store my firearms cleaned and just wipe a rifle bore dry before going shooting and this is the only one I ever had issue with.

Now, my next problem, how does one go about bluing the newely exposed steel, have any of ye lads done this, and keep it cheap

http://riflestocks.tripod.com/targetcrown.html

might give you a few ideas!