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Air Venturi General PCP & Avenger Guidance Requested

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WOB

Member
May 12, 2024
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Hello, my name is Bart. I am new to PCP's and I am in need of some guidance. I have purchased an Avenger .25 caliber and I am trying to understand its limitations In regards to slugs and proper setup in general. My compressor will arrive this coming week and I desire to learn all I can, so that I don't make a mistep:


- How can you tell what size slug the barrel can handle?

- Why does one "slug a barrel"?

- Are there aftermarket barrels for PCP's?

- Is there a rule of thumb when selecting slugs or pellets based on size?

- What do you wish you knew when you first started into PCP's?



I know that I will have more questions and I apologize if this seems to elementary, but I not even sure what to search for, it all too new at this point.

Thank you,
Bart
 
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It depends on what you expect of it I guess, some want long range accuracy while others mid range power. Slugging a barrel is done to get land and grove dimensions, look for tight/loose/rough spots. I personally cast and shoot 50. Gr slugs in a Hatsan flash for hunting/pest and am happy with the outcome. I tuned for just that project. On diameter it depends most you go over grove a hair but some will do better a bit under, let it tell you what it likes.
 
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Welcome to the forum!

It is all about accuracy. Your barrel is a certain size and if the slug is too big or small it will open up your groups because those need spin to stabilize and be accurate. Most of the time slugs need to go above 900 fps to spin quick enough to stabilize too. Also the barrel twist rate can effect the ability to shoot heavy for caliber slugs. Too slow and those heavy ones just corkscrew out. Or too tight and they deform and do the same. Too loose and they aren't spinning so... also not flying straight.

I have a .22 Avenger so I apologize I cannot help you with exact suggestions but I did find out mine likes 20.2 gr in .216 size going 950 ish fps but for 17.5 gr it needs .2165 and those shot 1018 fps average. More rifling engagement for the lighter weight because they're shorter. That can be applied to your .25 I'm sure.

This was at 30 yards:
20240511_155928~2.jpg

Especially right now since there is a 20% off coupon, I would highly recommend you visit Neilson Specialty Ammo (NSA) website and order some slugs after looking around on here for .25 size recommendations.

Yeah they make aftermarket barrels I think the maker is TJ or Troy Hammer you can search on this site but that's a big thing to take on because I hear it's a barrel blank and you need to finish it so it actually fits the Avenger.

First start in PCP? Get a compressor lol I hand pumped my Avenger for a year. I had put a 350cc bottle on it so it was even more pumps than the OEM tubes. Crazy.
 
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Empty


I appreciate the information. I guess the round fitment is really, just trial and error. Did you track exact diameters in order to find the right round fitment vs how they left the barrel?


I will order some of the slugs from NSA. I am actively searching for the heaviest slug that has been used with great accuracy. Of course, that does not mean that my exact rifle will perform perfect, nor the loose nut behind the wheel.


Thank you.
 
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WOB said:
Empty


I appreciate the information. I guess the round fitment is really, just trial and error. Did you track exact diameters in order to find the right round fitment vs how they left the barrel?


I will order some of the slugs from NSA. I am actively searching for the heaviest slug that has been used with great accuracy. Of course, that does not mean that my exact rifle will perform perfect, nor the loose nut behind the wheel.


Thank you.
Click to expand...
Yes it is a lot of trial and error but if you look around on this forum or anywhere else I'm sure someone will have some suggestions for sizes for the .25 cal

No I didn't measure the slugs myself, just ordered from NSA and shot each size and recorded the results on the target. The target was 10 shot groups at 30 yards. Lots say do 5 shot but 10 really shows you what really happens. Plus like for 20.2 .216 I jerked one so having 9 in the "real group" is better than just 4 if I only did a 5 shot group.

Heavy means you need more air to fire it at a good enough speed to stabilize. Also know that since the slug contacts the rifling pretty much the whole length vs a pellet which only touches at the head and skirt, the slugs naturally shoot slower than pellets to begin with. I shoot the 18.13 gr JSB pellet and 17.5 gr .2165 gr NSA slug about the same speed, for reference.

I'm not saying don't try for heaviest slug I'm just saying you'll need more air to get it to go fast enough to stabilize if it is heavy for caliber.

To my knowledge, NSA does not have a sampler pack (Sizes and weights) so I have had to purchase slugs in each size and weight and test them out.

Oh! I have something to add for "what do you wish you did when starting with pcp" I definitely recommend you get a chronograph. You cannot tune your airgun well without it. You can get ballpark by seeing what your target looks like after the group gets shot but you may be using more air than needed or something else may be out of balance. You want the hammer and regulator pressure in harmony, and it's been recommended here that you shoot the highest hammer spring setting at the regulator setting you're at, then get an average, and then tune back down to 95-97% of that peak fps to get to an economical tune where you are using the perfect amount of air to get fastest speed for the settings.
 
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