Snowpeak M25 .35 cal Does my barrel need help?

[Fado71]

Pics with vernier calipers is the actual extent of the damage internally, maybe a few mm's more but will check once i actually cut the offending part off.

[Fado71]

And here is the AS showing the muzzle tip eclipsing the holes

[bear air]

I didn't like that the air stripper holes were blocked by the barrel either. I'm enjoying your thread Fado. I appreciate you taking the time to post your efforts and results. It sure looks like your on your way to having a good shooter.

[Fado71]

I didn't like that the air stripper holes were blocked by the barrel either. I'm enjoying your thread Fado. I appreciate you taking the time to post your efforts and results. It sure looks like your on your way to having a good shooter.

I would think that the AS holes would not be covered by a muzzle tip on most guns but i dont have enough general gun knowledge to know for sure. Was yours the same, did you do anything to it?
I am having to cut my crown back and with some luck the right amount it should resolve this problem, 2 birds with one stone.

Glad to hear your enjoying the ride , I am happy to be able to leave the info for others who are likely to have similar problems, giving a little back for the great info i am receiving here from you guys.
Just a shame the barrel is in such bad shape right out the box but i am enjoying learning a new skill, so long as i dont ruin it in the process..... got all fingers crossed it does end up a decent shooter.

[bear air]

Im not even sure what I could do with the stripper holes Alex. I did contemplate putting a dab of jb weld on that side of the hole and then use my Dremel to make them proper air stripper holes. Cutting your barrel should fix that small issue. I'm a sucker for a cheap airgun lol. Plus I really enjoy learning from the guys here like Jason and so many others. For under $300 to my door I've actually been keeping an eye out to see if they are back in stock lol.

[avator]

There is a shroud right? If there is a shroud the AS might not bottom out on the threads leaving the AS holes clear of the barrel end.

[nervoustrigger]

Would it be better but slower, which I am fine with, to use patches on a shoe lace and compound to carry on removing material, my thinking it would work both the grooves and lands.

That’s the right idea, and yes I think it would be better in that respect.  However my concern is that the word slower will not do it justice
 
The preferred approach would be a cast lap and start with a rather coarse abrasive in the neighborhood of 120 – 180 grit.  If memory serves, it took me about 2 hours of intense lapping effort on my barrel to work out the tight region.  How long would it take to remove a comparable amount of material with a fine abrasive on a compressible patch?  Wild guess…10 hours?
 
Might be worth acknowledging that it would certainly soften the profile of the lands along the way, but as compared to a dowel wrapped with sandpaper which will ultimately remove the lands altogether, it’s still a better approach in my opinion.
 

I am also very lucky then, as my barrel does tighten up, almost as tight as the breech, at the choke, a good few inches back from the muzzle.  I will mark along the barrel on some tape…

Once you have the damaged rifling removed, please check it again and advise if the tightness remains constant all the way until the head of the pellet is right at the point of popping out into the world.  If so, that’s very fortuitous.  My guess is you’ll probably detect a little relaxation right at the end because the bore of a button-rifled barrel tends to open up slightly when  the OD is turned down for threading.
 
Regarding the air stripper, I agree that it is preferable for the radial holes to be unobstructed.  So shortening up the threaded portion to get rid of the damaged lands is beneficial here as well.  Though in a scenario like this where groups are multiple inches at 50yds, I don’t expect it is a major contributing factor.  Which reminds me, I strongly recommend you get your hands on some of the JSB or FX domes if you haven’t already.  Because even if you turn in the most amazing smithing effort of all time, you may not be able to recognize it if all you have for testing are the Snowpeak domes.

[bear air]

+1 on the jsb' & fx pellets.

[Fado71]

The deed has been done!

I have cut the crown back, i cut it back an extra two threads more than my last pics showed with the vernier's.

Gave it a quick bevel with a fine conical stone i had that fits in my drill, added autosol paste to lessen the stones cut and no pressure pressing down on the crown, finished with a coach bolt and more compound.
I only used autosol and mixed it with a little autobody coarse clear coat polishing paste for the coach bolt work as i can not find my valve grinding pastes anywhere.

Crown is perfectly 90deg from outer barrel edge.

Only thing is i think i can see one land still with some marking  ..

I noticed this before i beveled the crown, I thought i would do it as a practice in case i have to cut again and wont get a second chance to mess up and have to cut even more off those threads, think i could bevel a little more but was fairly happy with the result of the bevel, better than the burnt and gouged original anyway, it's a long way from being called finished.

Jason,
As i have some more barrel work to do i wondered, and here is my lack of experience showing, so going to ask anyway .

Will the needed barrel work (if i cast a lap) 'help' correct that last land imperfection at all, keeping well clear of the crown edge, it looks like the least damaged land that i had.

I guess the only real way to know is try shooting it but want to get the barrel polishing/lapping further along before i test and hand pump, still waiting on a compressor to come.

Or is more hacksaw the only way at this point?

I know you cut off more off your barrel but I am worried to take any more off and the AS be lose or not sit in a good alignment, i know you said a few good turns would hold it but it worries me as like i say, im new to this, not doubting you in anyway!

As for muzzle tightness, before any cutting i could feel the pellet loosen a little just at the start of the AS threads just like you described, less so than the choke.
(my 'tight' marks i put on the tape/barrel were as accurate as i could get them)

Obviously i would like to get the barrel shooting as well as can be expected for the price.
But this is for dealing with the wild hogs that destroy my farm every night.... max distance 50 meters, this isn't for field target shooting although i am a believer if your gonna shoot something then it should be done so it doesn't suffer and achieve and instant lights out.

As the pellets go, even back in my day spending a little more on pellets always paid off, i only got these to try the gun out and sight it in.
And mainly to see how 81grain punches from a modern pcp as the last air rifle i shot was a springer possible with 20flb's
Being as it is for hogs i will be looking at the JSB's and possibly some good solid slugs something like 120 grain later down the road.

I didn't think the AS eclipsing issue would effect the accuracy in anyway, i was more thinking it wasn't right and hope it might help reduce the report a little, happy to say after the cut the holes are now unrestricted.

[Fado71]

There is a shroud right? If there is a shroud the AS might not bottom out on the threads leaving the AS holes clear of the barrel end.

Good Point, i will measure that before i cut anymore off the crown but i think it runs up flush by some marks left on the AS base.... appreciate the input!

[avator]

No problem... worse case would be to cut a bit off the shroud. I would have a close look and see if I could catch enough threads and clear the stripper holes in the AS.
I wonder if you could screw the AS onto the barrel just enough to keep the AS holes clear then take the measurement for the shroud.

[bear air]

Nice work Alex. That barrel looks great. I think your going to be happy once the compressor and new pellets come. I've seen a great deal of improvement since I went through the process. Excited to see how it does and how it well it dispatches the little menaces.

[Fado71]

Today i have bought some supplies to make a handle for a cast lap.

But after searching the internet i cant find anything on where to cast the lap inside the barrel to get a good sized lap, maybe over thinking it with some saying to tap the end of the lead lap occasionally to make it swell and carry on lapping. Maybe i am over thinking it but the last thing i want to do is ruin the barrel.

My breech is the tightest part of my barrel so wonder should i cast it there or at the muzzle end ?

[nervoustrigger]

A muzzle pour that is 3” to 4” long is pretty much always a good choice. 
 
The option to do a breech pour is only viable if you’re working with an unmachined blank, else the lap will get stuck in the leade and/or barrel port.  And only useful if it’s an unchoked blank because otherwise the lap will not be able to get into the constricted region (as contrasted to a muzzle pour which is long enough to occupy both regions).
 
There is no scenario I am aware of where a mid-range pour would be advantageous.  Not to mention the challenge of getting it to fill out well.
 
Start by making sure the bore is clean and dry (no oil), and preheat the muzzle with a heat gun or propane torch to help obtain a well filled out casting.  I prefer a heat gun because there’s no way to overdo it…and to whatever extent it is slower is of no consequence because I have it going while I’m getting set up for the pour.
 
By the way, I no longer bother with occasionally compressing the lap to expand it.  When lapping with an abrasive coarse enough to perform any useful surface leveling, the particles occupy the infinitesimal gaps between the lap and bore where they perform the desired scrubbing action.

[Fado71]

A little update on the lead lapping progress.

With only one gun shop close by and they only had cleaning kits for rifles and shotguns the only thing i could get my hands on today to make a rod was some wooden dowel and some 4mm threaded rod.

With the lack of any decently stocked shops around me i also bought some 'fine' valve lapping compound.
I had read conflicting reviews on it's use, some say ok some say *(&^ no it will inbed itself.

In the UK i owned a large bodyshop and garage for most of my life and i have re-built hundreds of classic and modern engines and probably hand lapped a thousand valves and seats.
I know we are talking totally different materials here but to get a valve to seat and on some old classics if they dont seal 100% the old girl wont fire up, in order to get that perfect seal the faces must be free of any imperfections so my take (and in the gun world i am probably wrong and just made that shiny fire poker out of my barrel)  is that even if some does inbed it will have been smoothed off by the other broken down compound and the lap.  and I only used only a very fine smear.
Please feel free to tell me i just made a new fire poker

I chose to use the threaded rod as the threads will grab the lead better and thought the dowel might char anyway.
I sleeved the threaded rod with some fine rubber hose, like used in aquariums to prevent metal to metal contact and it actually worked pretty well, also with a good gap between it and barrel so as not to do any lapping with any compound stuck to the tubing.

Using an old pellet tin lid bent to form a spout as the wife wasn't happy i was looking in the spoon draw
I used a gas torch to melt down some of the first pellets i slugged when i started this and used those to pour a 2" lap, keeping the tip of the rod 1/4" in from the end of the lap to prevent scratching.

I'm not sure it looks like the lap has taken a good form when poured? the lands dont look very defined to me.

Partly pushed it out of the muzzle and cut a shallow grove around it to hold some compound.
I only used a very fine smear of the valve paste on each run.

It worked well with very little flex from the rod even passing the tight spots and with a light grip on the hose covered rod it rotated very well in the rifling.

After about 10 strokes i ran a clean patch and cleaning solvent down to clean out residue and slugged the barrel to check progress.
Keeping away from the crown i did about 6 sessions like this and worked a little more on the breech area which is now better, a little snug up until about 4" from the
breech but stopped the lapping there.
Now pellets are coming out without smearing but leaving a rifling mark, think i might need to take more pics tomorrow of the pellets, my phone needs day light to get a good macro shot.

The lands at the muzzle also look to have cleaned up, i cant see the greyed out marks in my last pics anymore, again not great pics and I really cant see much by eye.

I have stopped early on my work today for a few reasons, 'less is more' i think is the right way to go for someone like me without having ever done this before and secondly in case you all come tell me i have left fine valve paste in-bedded in the barrel and would hope other compounds and shooting would sort that out anyway but it can't be worse than it was.... i hope!

Thanks for all the input so far, you have all helped me with your advice and experience.
I just hope i haven't made you all gasp at your screens over the compound i used.

[Fado71]

Pellets from after the work.
One pic has a before and after comparison.

[Fado71]

A muzzle pour that is 3” to 4” long is pretty much always a good choice. 
 
The option to do a breech pour is only viable if you’re working with an unmachined blank, else the lap will get stuck in the leade and/or barrel port.  And only useful if it’s an unchoked blank because otherwise the lap will not be able to get into the constricted region (as contrasted to a muzzle pour which is long enough to occupy both regions).
 
Start by making sure the bore is clean and dry (no oil), and preheat the muzzle with a heat gun or propane torch to help obtain a well filled out casting.  I prefer a heat gun because there’s no way to overdo it…and to whatever extent it is slower is of no consequence because I have it going while I’m getting set up for the pour.
 
By the way, I no longer bother with occasionally compressing the lap to expand it.  When lapping with an abrasive coarse enough to perform any useful surface leveling, the particles occupy the infinitesimal gaps between the lap and bore where they perform the desired scrubbing action.

Was just making my last post when you posted.

I'm not sure i got the barrel warm enough, i think my lap looked a little 'dull' and clearly a little short, do you think it is worth pouring a new one tomorrow and giving a few more laps, i have just posted pics of results so far.
From breech for about 4" it is now snug not tight, then loosens a little and the ridges have calmed down, then about 4" from the muzzle it tightens again, breech and muzzle feeling more even in the snug feeling.

The lands seem to have cleared up but i will take some clearer pics tomorrow and if any different will post them for reference

Thanks again for taking the time to reply to my posts Jason and to others who have commented, you could have left me to Jason's and the Internet's articles without spending the time to give out such helpful words of wisdom.

[nervoustrigger]

Very cool…I like your ingenuity with the threaded rod and tubing.  Regarding the poured lap, it does indeed appear that it may not have filled out well.  Granted it’s kinda tricky to tell even in person after it has been used, let alone in a photo.  What I would say is it should be nice and shiny with distinct features when you inspect it shortly after pouring.
 
To your question, yes I agree it’s probably a good idea to pour a fresh one and do another run and go ahead and spend a little more time working the tight region near the breech end.  By the time you feel some improvement there, the abrasive will have broken down a bit and you can do a few passes further down to gauge things.  And based on how it feels, decide how much or how little scrubbing you want to do there.  If you are still seeing some land damage, you can make a judgement call on how far to carry it.

[sb327]

I’ve been following along. Jason always gives great advice in these matters. Good on you for following through with this project, it looks like you are making good progress. The only thing I might add is if you decide to do another run, make sure you get the good fill out of the lap that was discussed.

Thanks for sharing your project with us and documenting it well.

Dave

[avator]

See Alex? I told you not to give up on this thread.
The GTA is a great place to be and that's because of it's members.