Avenger Barrel Slugging...or, Getting ready for the "SLUGFEST!

[GerrywithaG]

 I am going nuts waiting for my compressor to get here to start testing my new Avenger. I didn't want to add this subject onto my last thread as Barrel Slugging is an art in it's own right. Yesterday when I had the rifle apart I forgot to slug the barrel, so I got it done this afternoon and figured I would snap a few pics for those of you who are new to slugging. I did not pull the shroud to do this, tho it is easier to do with the barrel in your hand...it is not a must.

The basic tools I used. You can come up with your own tool set and ideas better than mine I'm sure! You will need a good way to measure the slugs...no tape measures here guys, a caliper will work, but a good micrometer is best.

So, why do we jam wads of lead down our nice new clean accurate barrels? well, we are looking for some very important info to help choose ammo diameter, find oddities in the barrel bore, and feel for any tight or loose sections we may need to work around, or eliminate if we can. Before affordable bore cams slugging was an art passed on from Gunsmith to Apprentice while learning to lapp barrels.

I lightly blue taped the the 0.217" NSA Nielsen Specialty Ammo slug onto a Bamboo kabob skewer pointy end down, and started it into the crown square as I could with a light tap and the tape let the slug go into the muzzle.

I know I know some of you are freaking out cause I'm going backwards, but hey in the end it is an unfired metal pipe with grooves, no harm done. The slug needed a few firm hits to get it going into the bore. Go slowly, and don't use ANYTHING that can hurt the bore!

Once the slug is all the way into the bore pay close attention to the force needed to move it along, The perfect bore is snug and even resistance all the way down. If you get a super tight or loose spot, mark the "pusher rod" for later inspection. You can do as many slugs as you want til you are happy with the result. 1 or 10 makes no difference, It gets easier like everything.

The important tools IMO...the little drill bit fits right into the hollow point, and this tool is ideal for holding the slug during this inspection part of the job. Gently turn the slug and measure as you go. You will find a pattern of lands and grooves...mine were .2115" and .2140", yes the 4th decimal can matter, but I am about as OCD as they come...take your time, and save the slugs for later to compare after 20 or 30,000 rounds

So there it is! now you are a barrel slugger... have fun with it, be careful not to scratch the bore or crown, but it all can be fixed right!

Good night,

G.

 

[dizzums]

nice work .. very interested to see how it shoots ..

 

[lenweber2]

OK your part way done. Now what size to order for YOUR barrel. OH some barrels like a tight fit some a loose. Some like a flat base some a concave base. LOL only the start my friend.

 

[Roachcreek]

Glad to see someone is listening about slugging their barrel instead of buying one size fits all slugs and keeping them on the shelf because they do not group well.

A unchoked barrel can be slugged for groove dimensions from the muzzle, but I always do it from the chamber end.

I tap the lubbed slightly oversized for barrel diameter slug with silicone oil in with the rawhide mallet I cast with, then switch to an underbore 6 inch rod to get it started down the tube and finish with a roller bearing handled solid one piece cieaning rod.

All slugs need to be sized .001 to .0005 over groove diameter if the barrel is not choked. Choked barrels can shoot slugs, but you size them to your choke, or better yet, remove the choke with a hacksaw and recrown.

Choked barrels are generally slugged by tapping up a caliber specific slug with a small hammer, .005 over groove diameter is enough. Push the slug halfway down the barrel from the receiver or chamber end as described above and then push it out all the way back through the chamber. That will give you your barrels groove diameter. To get the diameter of your choke, push the slug out the muzzle.

It will not work well to slug a choked barrel from the muzzle.

Your slugs as said, should be sized to .0005 to .001 over groove diameter and never undersized for a unchoked barrel.
If you get the idea I prefer unchoked barrels for slugs your right, I have been cutting that choke off and recrowning for years, but recently I have gotten my 25 Kratos barrel to shoot MP Molds 48 grain bullet in a .254/.251 choked barrel, oddly enough loading the backwards gives one hole groups at my modest range, the boat tail first seems to mate better with the rather abrupt choke on the Kratos rather than a conventional nose first presentation. Sort of a round boat tail wadcutter if you will.

I also polish my slug barrels with #7 rubbing compound slightly and finish with Flintz on a jagged patch. It will extend cleaning intervals and hake cleaning easier, plus give you a slight velocity boost.



Regards,



Roachcreek

 

[GerrywithaG]

Glad to see someone is listening about slugging their barrel instead of buying one size fits all slugs and keeping them on the shelf because they do not group well.

A unchoked barrel can be slugged for groove dimensions from the muzzle, but I always do it from the chamber end.

I tap the lubbed slightly oversized for barrel diameter slug with silicone oil in with the rawhide mallet I cast with, then switch to an underbore 6 inch rod to get it started down the tube and finish with a roller bearing handled solid one piece cieaning rod.

All slugs need to be sized .001 to .0005 over groove diameter if the barrel is not choked. Choked barrels can shoot slugs, but you size them to your choke, or better yet, remove the choke with a hacksaw and recrown.

Choked barrels are generally slugged by tapping up a caliber specific slug with a small hammer, .005 over groove diameter is enough. Push the slug halfway down the barrel from the receiver or chamber end as described above and then push it out all the way back through the chamber. That will give you your barrels groove diameter. To get the diameter of your choke, push the slug out the muzzle.

It will not work well to slug a choked barrel from the muzzle.

Your slugs as said, should be sized to .0005 to .001 over groove diameter and never undersized for a unchoked barrel.
If you get the idea I prefer unchoked barrels for slugs your right, I have been cutting that choke off and recrowning for years, but recently I have gotten my 25 Kratos barrel to shoot MP Molds 48 grain bullet in a .254/.251 choked barrel, oddly enough loading the backwards gives one hole groups at my modest range, the boat tail first seems to mate better with the rather abrupt choke on the Kratos rather than a conventional nose first presentation. Sort of a round boat tail wadcutter if you will.

I also polish my slug barrels with #7 rubbing compound slightly and finish with Flintz on a jagged patch. It will extend cleaning intervals and hake cleaning easier, plus give you a slight velocity boost.



Regards,



Roachcreek

Excellent info there Roachcreek. I never had to deal with choked barrels in .22lr bench rifles, but everything else transitions fairly well. Trying to keep the original post somewhat short I left out what you explained above better then I could...thanks for that!

Knowing the Avenger barrel is choked, I slugged muzzle first thinking I need to find the tightest part of this barrel and work back from there to get my slug O.D.

As you might guess, I most likely will be eliminating the choke, or counter boring this barrel (not sure if you guys do that in air rifles?), but I am going to shoot it as is before cutting on a possibly awesome tube!

After we find out what kind of shooter it is, I am going to do a thread on making a die for swageing all those lonely slugs sitting on the shelf! but that's for another day....

Thanks again for the help,

G.

 

[thomasair]

I think you will find that much of what you learned from Rimfire BR will be fairly useless in air rifles shooting slugs…especially so if you are going to try to build an air rifle worthy of BR shooting. The propulsion methods are at completely different ends of the spectrum. One creates heat…the other removes heat. One is a very high pressure for a very short period…the other is very low pressure for a long time. You will progress quicker if you don’t treat them as the same.

Good luck to you!

Mike 

 

[GerrywithaG]

UPDATE: After reading Roachcreeks post I figured I would show you all my notes from slugging my barrel. I think I know why these rifles shoot so well after seeing this profile. What do you all think?

G.

 

[GerrywithaG]

I think you will find that much of what you learned from Rimfire BR will be fairly useless in air rifles shooting slugs…especially so if you are going to try to build an air rifle worthy of BR shooting. The propulsion methods are at completely different ends of the spectrum. One creates heat…the other removes heat. One is a very high pressure for a very short period…the other is very low pressure for a long time. You will progress quicker if you don’t treat them as the same.

Good luck to you!

Mike

I won't get anywhere disagreeing with you! I will do my best to forget the powder guns. Thanks for the advise...

G.

 

[Kgphotos]

Quick question concerning a barrel with no choke. If I wanted to try testing slugs with no choke on my FX Crown MK2 600mm would it work to buy a 700mm liner and then cut it back to 600mm and recrown the muzzle? I think that the choke is near the end of the liner and removing 100mm would probably remove that choke. Has anybody tried this approach? Thanks for your help.

Kenny

 

[DesertSilver]

Glad to see someone is listening about slugging their barrel instead of buying one size fits all slugs and keeping them on the shelf because they do not group well.

A unchoked barrel can be slugged for groove dimensions from the muzzle, but I always do it from the chamber end.

I tap the lubbed slightly oversized for barrel diameter slug with silicone oil in with the rawhide mallet I cast with, then switch to an underbore 6 inch rod to get it started down the tube and finish with a roller bearing handled solid one piece cieaning rod.

All slugs need to be sized .001 to .0005 over groove diameter if the barrel is not choked. Choked barrels can shoot slugs, but you size them to your choke, or better yet, remove the choke with a hacksaw and recrown.

Choked barrels are generally slugged by tapping up a caliber specific slug with a small hammer, .005 over groove diameter is enough. Push the slug halfway down the barrel from the receiver or chamber end as described above and then push it out all the way back through the chamber. That will give you your barrels groove diameter. To get the diameter of your choke, push the slug out the muzzle.

It will not work well to slug a choked barrel from the muzzle.

Your slugs as said, should be sized to .0005 to .001 over groove diameter and never undersized for a unchoked barrel.
If you get the idea I prefer unchoked barrels for slugs your right, I have been cutting that choke off and recrowning for years, but recently I have gotten my 25 Kratos barrel to shoot MP Molds 48 grain bullet in a .254/.251 choked barrel, oddly enough loading the backwards gives one hole groups at my modest range, the boat tail first seems to mate better with the rather abrupt choke on the Kratos rather than a conventional nose first presentation. Sort of a round boat tail wadcutter if you will.

I also polish my slug barrels with #7 rubbing compound slightly and finish with Flintz on a jagged patch. It will extend cleaning intervals and hake cleaning easier, plus give you a slight velocity boost.



Regards,



Roachcreek

Excellent info there Roachcreek. I never had to deal with choked barrels in .22lr bench rifles, but everything else transitions fairly well. Trying to keep the original post somewhat short I left out what you explained above better then I could...thanks for that!

Knowing the Avenger barrel is choked, I slugged muzzle first thinking I need to find the tightest part of this barrel and work back from there to get my slug O.D.

As you might guess, I most likely will be eliminating the choke, or counter boring this barrel (not sure if you guys do that in air rifles?), but I am going to shoot it as is before cutting on a possibly awesome tube!

After we find out what kind of shooter it is, I am going to do a thread on making a die for swageing all those lonely slugs sitting on the shelf! but that's for another day....

Thanks again for the help,

G.

I've been told that the avenger barrel is the same as the liberty and Aspen barrel and they aren't choked but not having a avenger I can't say for certain.

 

[Ezana4CE]

Not to hijack this thread @GerryWithaG, but the guy in this video demonstrates slugging fairly easily https://m.youtube.com/watch?v=2lMp_nahuMI It looks very similar to what you describe above.

I thought it would be worth adding to the thread for future readers and viewers. If you’d like me to remove it from your thread please let me know.