I've finally finished experimenting with swaging and shooting slugs out of the Veteran long's CZ barrel and am finally getting around to experimenting with a new barrel I purchased a couple months back from Airgun Heaven. Here is how the barrel compares to the stock CZ barrel:
On first inspection of the barrel, it looks like it is well made. The ends are machined to the same dimensions as the stock CZ barrel.The stock barrel has an o-ring below the threads that screw into the breach. The new barrel didn't have one, but I fitted one just in case. I gave the barrel a good cleaning and could tell immediately that the barrel has a much bigger diameter than the stock CZ barrel.
Bore scope video of the CZ and Slug Barrels:
https://youtu.be/zaEbOOeBHII
While I had the barrel off the gun I took the opportunity to push a variety of sizes of pellets and slugs down the barrel to try to "size" it. I have been swaging my own slugs and experimenting with the CZ barrel for the past year or so. Most of the swaged slugs I have practically fell straight through. There was minimal engagement with the rifling
. I have experimented with powder coating slugs and had several that were .219 - .220 in diameter. Even these felt far too easy to push through.
So I tried pushing pellets through. The pellets I pushed through showed little rifling on the heads and the skirts were only compressed to about .22 to .221" diameters. This got me worried because I have only 1 slug that is such a large diameter.
So I started test shooting. As suspected JSB KO .216 scattered all over the place, as did my custom swaged slugs. Their diameter is just too small. Do I want to invest in a new set of dies to experiment with this barrel? I don't know. I haven't tried any of my NSA slugs yet because the ones I own are all .217 or .2165 sized. I'm not optimistic. I was able to get decent groups with the H&N .218 (25 gr?). They shot better than the JSB Monster Redesigns. The one slug I have that seemed like it would have a wide enough diameter are the Apex Ammo which are sized to .220.
Initial groups while sighting them in and getting the velocity up to 890 fps (63.3 FPE
) looked promising. However, they were unimpressive when I shot groups at 27 yards on a test target to share with you guys (see below).
So far the .218 slugs look most promising. I have lots of more tests I need to complete, but bottom line is if you are/were considering purchasing one of these barrels, I'd hold off until someone can show they can get them shooting better than the standard CZ barrel.
UPDATE: 7/2/2021
Ordered several larger diameter slugs to experiment with in the .218 to .223 inch diameter range. As you can see from the chart, none of the 4 NSA slugs I tried in the .218 diameter shot well. All the rest of the new slugs I tried are from AVS. He swages slugs in the .2183, .2193, .2213, and .223 sizes. I've had great luck with his slugs in the past shooting out of my CZ barrel.
I noticed that for the same weight slugs that the .2213 diameter slugs had the highest velocity. My thinking here is the smaller diameter slugs are allowing a bit of air around the projectile that is causing the loss in velocity. The .223 diameter slugs are slightly faster than the .2213 in lighter weight slugs but as the slug gets longer, lose this advantage for a reason that escapes me.
Here is a graph of average group sizes based on diameter:
This graph and the velocity data mentioned earlier show that this barrel prefers a slug with a diameter somewhere in the .220 area. I'm going to give the barrel a good polish and collect more data on the most promising projectiles.
On first inspection of the barrel, it looks like it is well made. The ends are machined to the same dimensions as the stock CZ barrel.The stock barrel has an o-ring below the threads that screw into the breach. The new barrel didn't have one, but I fitted one just in case. I gave the barrel a good cleaning and could tell immediately that the barrel has a much bigger diameter than the stock CZ barrel.
Bore scope video of the CZ and Slug Barrels:
https://youtu.be/zaEbOOeBHII
While I had the barrel off the gun I took the opportunity to push a variety of sizes of pellets and slugs down the barrel to try to "size" it. I have been swaging my own slugs and experimenting with the CZ barrel for the past year or so. Most of the swaged slugs I have practically fell straight through. There was minimal engagement with the rifling
. I have experimented with powder coating slugs and had several that were .219 - .220 in diameter. Even these felt far too easy to push through.So I tried pushing pellets through. The pellets I pushed through showed little rifling on the heads and the skirts were only compressed to about .22 to .221" diameters. This got me worried because I have only 1 slug that is such a large diameter.
So I started test shooting. As suspected JSB KO .216 scattered all over the place, as did my custom swaged slugs. Their diameter is just too small. Do I want to invest in a new set of dies to experiment with this barrel? I don't know. I haven't tried any of my NSA slugs yet because the ones I own are all .217 or .2165 sized. I'm not optimistic. I was able to get decent groups with the H&N .218 (25 gr?). They shot better than the JSB Monster Redesigns. The one slug I have that seemed like it would have a wide enough diameter are the Apex Ammo which are sized to .220.
Initial groups while sighting them in and getting the velocity up to 890 fps (63.3 FPE
) looked promising. However, they were unimpressive when I shot groups at 27 yards on a test target to share with you guys (see below).So far the .218 slugs look most promising. I have lots of more tests I need to complete, but bottom line is if you are/were considering purchasing one of these barrels, I'd hold off until someone can show they can get them shooting better than the standard CZ barrel.
UPDATE: 7/2/2021
Ordered several larger diameter slugs to experiment with in the .218 to .223 inch diameter range. As you can see from the chart, none of the 4 NSA slugs I tried in the .218 diameter shot well. All the rest of the new slugs I tried are from AVS. He swages slugs in the .2183, .2193, .2213, and .223 sizes. I've had great luck with his slugs in the past shooting out of my CZ barrel.
I noticed that for the same weight slugs that the .2213 diameter slugs had the highest velocity. My thinking here is the smaller diameter slugs are allowing a bit of air around the projectile that is causing the loss in velocity. The .223 diameter slugs are slightly faster than the .2213 in lighter weight slugs but as the slug gets longer, lose this advantage for a reason that escapes me.
Here is a graph of average group sizes based on diameter:
This graph and the velocity data mentioned earlier show that this barrel prefers a slug with a diameter somewhere in the .220 area. I'm going to give the barrel a good polish and collect more data on the most promising projectiles.
