Air Venturi Air Venturi Avenger, Spiraling Pellets, Lil' Help Please

[joeyw007]

Hey peoples how's everyone doing. I just got into PCPs about 3 weeks ago. I picked up a Gamo Arrow and it shoots great using Crosman Premier 14.3g .22 hollow points. I decided to grab an Avenger, DonyFL 1/2 20 UNF adapter/barrel stabilizer, Tanto moderator, Saber Tactical upgraded pic rails and a descent compressor. I finished putting it all together, filled her to about 3500 PSI and took it out. I'm shooting the same 14.3g Crosman hollow points I shoot from my break barrels and from my Gamo Arrow, and I can see the pellet start to spiral at about 20 yards. I'm only shooting to 50 at the most, 9 times out of 10. At 50 I'm having to hold down 2 mil in my scope and left 1mil. The pellets land right on top of each other, nearly. I tried dropping the regulator down to 1300 PSI and no preload tension on the HS to 1 1/2 turn in on the HS. Also, many 1/4 turns between. I couldn't get the velocity below 880. Do I need to run a heavier pellet to get rid of the spiraling. None of my other guns spiral at all that I can see and hold excellent groups. Sub MOA at 50 yards so 1/2" groups. If a heavier pellet is the answer does anyone have any recommendations? There are so many choices. Oh, to add, I clean my pellets, dry them well and lube them with REM Oil. A very thin coat, they aren't dripping wet with lubrication. I don't know, I've found cleaning and lubing like this works very well for me. Thanks

 

[Vetmx]

I find Crosman pellets to be pretty inconsistent but I have not tried the new single die pellets. 880 fps shouldn't be too fast but if you are having to greatly reduce the hammer spring to get to that velocity is suggests the regulator needs to be reduced if you want to shoot a pellet that light. Heavier pellets is the other way to slow things down. I think H&N pellets are as well made as JSB and several of my guns prefer them. The H&N Baracuda Match is the best pellet I have found for my P35-22. 21 grains. But I agree that JSB 18s are worth trying. Either will be more consistent and tend to shoot better than Crosmans in my experience.

Anybody who doesn't think spiraling is related to the tune should review the videos by Ted's holdover. He's pretty convinced it is and since he's won major 100y target shooting contests I tend to listen to him. But 880 shouldn't be too fast except perhaps if the wind is high. But putting the gun into a tune it doesn't like to get there seems like a risk too.

Your second paragraph is very important and often overlooked. I just went through it with a high end gun with high end barrel build. Just because you are in the “proper” speed window for what we think pellets like, doesn’t mean that how your gun is set to achieve that window speed is doing the pellet any favors.

 

[jarmstrong]

only my Gamo Urban likes Crosman domes, nothing likes the hollow points
that why my pellet shelf is full of FX in 5.52 head size,,, as size matters, to my guns

also could be ruff leade causing pellet deformation,,, scwraf, I have seen it at the crown also on a new barrel

 

[JimD]

This is admittedly a bit of an extreme retune but my P35-25 has convinced me that "a new barrel is required" is at least at times over prescribed. My 25 caliber was my first P35 and I liked it so much I bought one in 22 and another in 177 as soon as Krale had them in stock. It would get 3 H&N FTTs within about 1/4 inch sometimes but not consistently. I still took 18 squirrels with it, however. But when I started shooting 30 yard challenge targets it didn't do very well. I did not put a higher magnification scope on it but using it's 4-14 Primary Arms scope I shot a 155 (out of 200). I tried other pellets and tunes and decided it needed a barrel. So I looked around and couldn't find any drop ins. My P35-22 and 177 are much more accurate than this so I ordered another barrel from SPA through Krale.

Then I decided to put an Extreme Airguns bigger plenum on it. I thought I was getting ready for the new barrel to arrive. But I tried it. With the 4-14 barrel I shot a 177 and with a 32X scope a 194. My new barrel is slightly worse than this.

I am convinced the biggest factor is getting a pcp to shoot like you want is trying pellets until you find one the gun likes. I've tried adjusting velocity in my P35-25 and 177 over a wide range and not found it very helpful. The hammer spring setting for a given regulator setting certainly affects accuracy but the best setup at different regulator settings seems to shoot about the same. I stay below 900 fps. The plenum upgrade may have affected my P35-25 so much because it needed it to get 34 grain pellets up to 800 fps. But whatever the reason, the retune fixed my "bad barrel". I am still hoping to do better than a 194, ideally another 200 (like my P35-22).

I'm not arguing a retune will fix every accuracy issue. I would test a lot of different pellets before deciding the barrel needs to be replaced, however.

 

[GenXer]

I'm not arguing a retune will fix every accuracy issue. I would test a lot of different pellets before deciding the barrel needs to be replaced, however.

I think that one could argue that if the barrel has to be in a certain tune to be accurate that it could still be a bad barrel.

With all due respect finding one pellet at one velocity that makes it accurate doesn't mean nothing is wrong with the barrel.

My most accurate guns shoot well in a wide range of velocity with more than one kind of ammo and it is my opinion that's how it should be. I respect your opinion as well and that's all I have to say, about that.

 

[Vetmx]

I think that one could argue that if the barrel has to be in a certain tune to be accurate that it could still be a bad barrel.

With all due respect finding one pellet at one velocity that makes it accurate doesn't mean nothing is wrong with the barrel.

My most accurate guns shoot well in a wide range of velocity with more than one kind of ammo and it is my opinion that's how it should be. I respect your opinion as well and that's all I have to say, about that.

I agree with this also. I’ve had guns that I bent over backwards and split hairs to get them to shoot what could be acceptable. A couple magazines into testing a new barrel I finally machined for those guns had me thinking about all the time and lead I wasted on the previous bad barrel. Everything just got easier and way more leeway.

 

[joeyw007]

I respect that opinion but every single time I've worked on a rifle that made the pellets spiral, which is several times, a new barrel is what it took to fix it so I'm going to continue to go with my own hands on experience vs. 'a guy on YouTube said' when I make suggestions.

I fired ten 19g Crosman pellets at 50 yds and ten 21.54g Gamo Competition Pellets at 50 yds. It's holding 1/2" groups with both being fed via magazine. Didn't have time to setup the chronograph. That said, I need to check velocity and finish fine tuning for this weight of pellet. Looks like I it was just slinging those lite weight pellets way too hard. No spiraling to speak of. Thanks for all the input everyone. I was worried there for a bit, but all seems good now!

 

[GenXer]

I agree with this also. I’ve had guns that I bent over backwards and split hairs to get them to shoot what could be acceptable. A couple magazines into testing a new barrel I finally machined for those guns had me thinking about all the time and lead I wasted on the previous bad barrel. Everything just got easier and way more leeway.

Every time I see the term "pellet picky" my brain says "barrel is whack".

I fired ten 19g Crosman pellets at 50 yds and ten 21.54g Gamo Competition Pellets at 50 yds. It's holding 1/2" groups with both being fed via magazine. Didn't have time to setup the chronograph. That said, I need to check velocity and finish fine tuning for this weight of pellet. Looks like I it was just slinging those lite weight pellets way too hard. No spiraling to speak of. Thanks for all the input everyone. I was worried there for a bit, but all seems good now!

Glad all is good when you shoot heavy pellets which are more stable and more accurate in almost any gun. If it were me I would want it to be able to shoot more than just heavy pellets with accuracy. To each his own.

 

[joeyw007]

Every time I see the term "pellet picky" my brain says "barrel is whack".

Glad all is good when you shoot heavy pellets which are more stable and more accurate in almost any gun. If it were me I would want it to be able to shoot more than just heavy pellets with accuracy. To each his own.

I feel the same way as you. I shoot a lot! So, a cheaper pellet for lots of plinking is ideal. I'm going to spend more time with the gun, try some different pellets, get the tuning part square in my mind, and try them again later. Stacey at Air Venturi told me it should be able to send them without issue so it could have been something I did wrong. Just have to figure out what it was or maybe my barrel just doesn't like them. In any event I just wanted some input from the community, and all has been much appreciated. You know things to try, possible mistakes. YouTube is a useful resource but only to an extent in certain situations. Hey, if I can't get it to sling those Crosman 14.3g straight I might be the case I need to RMA it. Any thoughts on crowning the barrel proper. I have the correct tools to get it done right. Just not sure if it's worth it or not. Seen a lot of info saying not to worry about it. Thanks again everyone. Happy shooting!

 

[GenXer]

I feel the same way as you. I shoot a lot! So, a cheaper pellet for lots of plinking is ideal. I'm going to spend more time with the gun, try some different pellets, get the tuning part square in my mind, and try them again later. Stacey at Air Venturi told me it should be able to send them without issue so it could have been something I did wrong. Just have to figure out what it was or maybe my barrel just doesn't like them. In any event I just wanted some input from the community, and all has been much appreciated. You know things to try, possible mistakes. YouTube is a useful resource but only to an extent in certain situations. Hey, if I can't get it to sling those Crosman 14.3g straight I might be the case I need to RMA it. Any thoughts on crowning the barrel proper. I have the correct tools to get it done right. Just not sure if it's worth it or not. Seen a lot of info saying not to worry about it. Thanks again everyone. Happy shooting!

If you really want a good crown, remove the barrel, and take it to a well respected gunsmith who has crowned hundreds of barrels.

Many will say you can do it yourself, and you can, and it can be successful. However a gunsmith will be able to tell you if the barrel is true, and, he's a gunsmith. It's his job to get it perfect. No wondering. No wasted time. Just drop it off, pick it back up, pay the man. (Don't send a barrel out.) In the meantime you probably gain a great resource.

 

[joeyw007]

I'm an AGI certified gunsmith. I've done many barrels. This is why I have the hundreds and hundreds of dollars worth of crowning tools. Just never crowned an air gun barrel. Just curious if it's worth the effort on an air gun. I'm literally working on week three of getting serious with air guns and I like to soke up info like a sponge when I get into a new hobby.

 

[GenXer]

I'm an AGI certified gunsmith. I've done many barrels. This is why I have the hundreds and hundreds of dollars worth of crowning tools. Just never crowned an air gun barrel. Just curious if it's worth the effort on an air gun. I'm literally working on week three of getting serious with air guns and I like to soke up info like a sponge when I get into a new hobby.

Absolutely it is worth it to crown an airgun barrel. They are nowhere near as quality controlled as firearm barrels. Now that you say that, I wonder why this thread even exist ... I would have crowned it day 1. Never met a gunsmith who didn't know what swarf is...

 

[joeyw007]

Absolutely it is worth it to crown an airgun barrel. They are nowhere near as quality controlled as firearm barrels. Now that you say that, I wonder why this thread even exist ... I would have crowned it day 1. Never met a gunsmith who didn't know what swarf is...

I call them burs. Never heard the term swarf. Different circles, I guess. I'll check and see if doing so will void the warranty then proceed as best. I know it can't hurt done proper, just wasn't sure about the impact with an air gun. I mean barrel to DonyFL adapter with barrel shroud which chokes the front end down and then into a Tanto moderator. The difference can't be too astounding but then maybe it could be if pushing 100 yds.

 

[GenXer]

I call them burs. Never heard the term swarf. Different circles, I guess. I'll check and see if doing so will void the warranty then proceed as best. I know it can't hurt done proper, just wasn't sure about the impact with an air gun. I mean barrel to DonyFL adapter with barrel shroud which chokes the front end down and then into a Tanto moderator. The difference can't be too astounding but then maybe it could be if pushing 100 yds.

Without even being a little dramatic it can be night and day at 25 yards. Please do it then tell us how those 14.3 shoot with no moderator.

It won't void your warranty. Because you won't tell them. If you don't tell them, how would they know?

 

[joeyw007]

I'll see how she shoots over the next few weeks. If it'll hold 1/2" or tighter groups at 50 I may not bother. However, sometimes us gear heads get bored. If you don't tell I won't, LOL!

 

[JimD]

This is crude relative to what a gunsmith with proper tools can do but I usually polish the crown with JBs on a brass round headed screw (in a drill). It makes the crown look significantly better but I tried targets before and after this process on my "new barrel" for the 25 and accuracy did not change. I still think it's a good idea if you have the tools to clean up the crown.

I agree that a barrel that requires exactly the right conditions to be accurate is probably not a "good barrel". One difference between the new barrel for my P35-25 and the old barrel is the accuracy after I dropped the regulator a little bit (less than 10 fps). The new barrel got significantly worse in accuracy but the old barrel did not. Velocity changes from ambient temperature changes as much as my hammer spring tweak changed the guns velocity. The new barrel was almost as accurate initially as the old (with a pellet I wanted it to shoot well) but the change with the tweak convinced me to use the old barrel.

Neither of these barrels is terribly pellet fussy but they do have their preferences. The new barrel's favorite is the H&N Baracuda (31 grains). It shot a 191 with this pellet. It shot in the mid to high 180s with the JSB King Heavies MKII the old barrel prefers (34 grain). The old barrel is the opposite. As high as a 194 with the JSBs, upper 180s with the Barracudas. There are pellets both barrels put into over a 1 inch group at 30 yards but these pellets go into 1/4 inch groups (5 shot) to maybe 1/2 inch if I mess up or the wind kicks up. JSB and FX 25.4s are almost as good as the heavier pellets too. On one target the 25.4s gave me smaller groups. That's why I like using a few 30 yard challenge targets. It seems to make accuracy differences more apparent than groups. Harder to get 24 good shots than 5 or 10.

 

[joeyw007]

This is crude relative to what a gunsmith with proper tools can do but I usually polish the crown with JBs on a brass round headed screw (in a drill). It makes the crown look significantly better but I tried targets before and after this process on my "new barrel" for the 25 and accuracy did not change. I still think it's a good idea if you have the tools to clean up the crown.

I agree that a barrel that requires exactly the right conditions to be accurate is probably not a "good barrel". One difference between the new barrel for my P35-25 and the old barrel is the accuracy after I dropped the regulator a little bit (less than 10 fps). The new barrel got significantly worse in accuracy but the old barrel did not. Velocity changes from ambient temperature changes as much as my hammer spring tweak changed the guns velocity. The new barrel was almost as accurate initially as the old (with a pellet I wanted it to shoot well) but the change with the tweak convinced me to use the old barrel.

Neither of these barrels is terribly pellet fussy but they do have their preferences. The new barrel's favorite is the H&N Baracuda (31 grains). It shot a 191 with this pellet. It shot in the mid to high 180s with the JSB King Heavies MKII the old barrel prefers (34 grain). The old barrel is the opposite. As high as a 194 with the JSBs, upper 180s with the Barracudas. There are pellets both barrels put into over a 1 inch group at 30 yards but these pellets go into 1/4 inch groups (5 shot) to maybe 1/2 inch if I mess up or the wind kicks up. JSB and FX 25.4s are almost as good as the heavier pellets too. On one target the 25.4s gave me smaller groups. That's why I like using a few 30 yard challenge targets. It seems to make accuracy differences more apparent than groups. Harder to get 24 good shots than 5 or 10.

I have an 11-degree T handle crown tool and a 45-degree T handle crown tool with various sized guide rods for many calibers along with a nice T handle chamfering tool with guide rods. I have watched a few videos on YouTube where guys did it the way you are speaking of. Kind of made me cringe a bit but if you have the eye, patients, and skills I have no doubt it can be done like that. Probably not to high precision standards but good enough for an air gun. I have turned a crane rod from bar stock for revolver when my lathe was down once just to see if I could do it. I'm learning pretty quick with this regulated air gun that weather conditions and air temps really matter. Except for that Gamo Arrow. That thing doesn't give two hoots. It shoots consistent no matter. Supposed to have something to do with the turbo or lightning or something like that valve they use. The shot string is really consistent from 3300 PSI all the way down to 1500. About 40 to 50 good shots but you will be holding high just a bit on those last ten if you stretch it to 50 shots. If I had to make an educated guess as to why they were spiraling after seeing a heavier domed pellet fly great. I'd guess they were moving way too fast for a hollow point. After I spend more time with this gun I'll know if the barrel needs to be replaced. Let's hope not for the sake of simplicity. I really like the way these Gamo pellets shoot but I'm going to order some JSBs and H&Ns as well just to experiment with. I do want a cheap alternative for just plinking in the back yard because I'd rather be shooting. Almost more than anything else a man can do

 

[GenXer]

I have an 11-degree T handle crown tool and a 45-degree T handle crown tool with various sized guide rods for many calibers along with a nice T handle chamfering tool with guide rods. I have watched a few videos on YouTube where guys did it the way you are speaking of. Kind of made me cringe a bit but if you have the eye, patients, and skills I have no doubt it can be done like that. Probably not to high precision standards but good enough for an air gun. I have turned a crane rod from bar stock for revolver when my lathe was down once just to see if I could do it. I'm learning pretty quick with this regulated air gun that weather conditions and air temps really matter. Except for that Gamo Arrow. That thing doesn't give two hoots. It shoots consistent no matter. Supposed to have something to do with the turbo or lightning or something like that valve they use. The shot string is really consistent from 3300 PSI all the way down to 1500. About 40 to 50 good shots but you will be holding high just a bit on those last ten if you stretch it to 50 shots. If I had to make an educated guess as to why they were spiraling after seeing a heavier domed pellet fly great. I'd guess they were moving way too fast for a hollow point. After I spend more time with this gun I'll know if the barrel needs to be replaced. Let's hope not for the sake of simplicity. I really like the way these Gamo pellets shoot but I'm going to order some JSBs and H&Ns as well just to experiment with. I do want a cheap alternative for just plinking in the back yard because I'd rather be shooting. Almost more than anything else a man can do

What is this "good enough for an airgun" stuff you keep saying though? As a tool, it is only useful if it's accurate. I guess I don't see a single bit of difference myself

As a gunsmith, why are you watching amateur's YouTube videos on how to crown an airgun barrel? Forgive me but this doesn't really add up. If you're new at it, it's ok to say so. The way you're on about your tools it sounds like maybe you just got certified and just want to tell someone about it.

Certified don't always mean much. I went to MMI with a lot of people who are now certified motorcycle technicians that I wouldn't let work on my weed eater.

Not picking on you but again some of the stuff you're saying just doesn't make sense to me. Every gunsmith I have ever known, which is several, would already have that barrel chucked up.

 

[MongooseV8]

I'll see how she shoots over the next few weeks. If it'll hold 1/2" or tighter groups at 50 I may not bother. However, sometimes us gear heads get bored. If you don't tell I won't, LOL!

We had a similar issue with a 177 Avenger. We had it turned all the way down and could not get a wide variety of pellets to go slow enough for accuracy. As others have posted, if you push a pellet too fast, or too high an rpm they will spiral all over the place. The 22 Cal Avengers we have all do really great with 15.89g Hades and even better with the heavier pellets like the 21.14g Barracudas. Mine also shoots Nielsens 17.5g slugs nicely.

 

[joeyw007]

We had a similar issue with a 177 Avenger. We had it turned all the way down and could not get a wide variety of pellets to go slow enough for accuracy. As others have posted, if you push a pellet too fast, or too high an rpm they will spiral all over the place. The 22 Cal Avengers we have all do really great with 15.89g Hades and even better with the heavier pellets like the 21.14g Barracudas. Mine also shoots Nielsens 17.5g slugs nicely.

Thanks for that tidbit. I figured I was having the same problem. Much appreciated.

 

[Vetmx]

I'm an AGI certified gunsmith. I've done many barrels. This is why I have the hundreds and hundreds of dollars worth of crowning tools. Just never crowned an air gun barrel. Just curious if it's worth the effort on an air gun. I'm literally working on week three of getting serious with air guns and I like to soke up info like a sponge when I get into a new hobby.

A barrel is a barrel. No matter what it’s on. If it shoots a projectile, Elvis has to leave the building on two feet and not wobbling. How a gunsmith wouldn’t know this is beyond me but like you said, different circles.