AEA Precision Challenger Bullpup .45

[Airgun-hobbyist]

That's a relief to hear about the length for mag. Worrying to hear of diameter. I was planning on eventually getting a swage die for my press that makes slugs for it, but the max diameter I can make on it is .458 so if they have to be bigger to seal I may have to buy slugs instead of swaging them, or get into casting

Could you please let us know what your particular bore slugs at as well. It would be great to know that information so we can see if there is at consistency among the bore sizing so that new owners can get the proper molds and or dies, and even order correct sized ammo from the various manufacturer's who produce slugs. 

 

[Asher]

Ok I just got it. Have to get ready for a night shift but I will try to slug the barrel later, assuming the. 457 slugs will accomplish that. I got an assortment of slugs to test from NSA. The 196, 220, 240, 254, 260 and 290 grain slugs. It seems only the 196, 220, and the 240s will fit in the mag, but all of them are short enough to single load. Because the noses are very cone shaped on a lot of the slugs I got, I suspect a rounder shape might allow a bit heavier slug to fit, bit I wouldnt expect anything much heavier than 250 grains to fit. Works for me as that's about the weight I intended to shoot most anyway

 

[Ironman482]

I slugged mine today ,same as air- gun hobbyist 461, another poster on gta got 461 also, so looks kinda consistent, I've got three weights of 457 slugs in the mail today from NSA , I'll powdercoat some tonite , my 461 sizer will be here next week , I'll test some unsized if they're close to 461 .

 

[Asher]

Dang. Sounding like if I want to make my own I'll have to get into casting. My swage press can only handle up to .457 or .458

 

[Asher]

I fired the gun for the first time today. Still have compressor issues so my big tank only had 2800 psi to test it with. I did hand pump the gun to 3600 first though. Shot over the crony until velocity dipped. First three with the 240 grain were all right around 815 fps. Disappointed but not suprised. I already knew .457 diameter isnt wide enough from this thread. I just slapped the scope from my .25 huben on and to my suprise, it was almost dead on with no adjustment.



Gun seems accurate. Not sure if its weight reduces recoil by much but I'd like to believe that that is a plus side of it being so dang heavy. Sometimes the cocking wasnt smooth. Hope that can be improved. Trigger is slightly heavy. My initial impressions are that I really really like it. I especially like having a 6 shot magazine. Super rare on a big bore. 



Where can I get larger slugs? Anyone done enough testing to know exactly what diameter is optimal? NSA doesnt seem to go bigger than .457

 

[Airgun-hobbyist]

I fired the gun for the first time today. Still have compressor issues so my big tank only had 2800 psi to test it with. I did hand pump the gun to 3600 first though. Shot over the crony until velocity dipped. First three with the 240 grain were all right around 815 fps. Disappointed but not suprised. I already knew .457 diameter isnt wide enough from this thread. I just slapped the scope from my .25 huben on and to my suprise, it was almost dead on with no adjustment.



Gun seems accurate. Not sure if its weight reduces recoil by much but I'd like to believe that that is a plus side of it being so dang heavy. Sometimes the cocking wasnt smooth. Hope that can be improved. Trigger is slightly heavy. My initial impressions are that I really really like it. I especially like having a 6 shot magazine. Super rare on a big bore. 



Where can I get larger slugs? Anyone done enough testing to know exactly what diameter is optimal? NSA doesnt seem to go bigger than .457

I have an easy working solution for the NSA slug sizing in the large bored .457 Challenger barrel, which slugs out at over .4615". I have both NSA 220 and 240 grain dimple/dish back slugs. I take a long punch, about .125" diameter that fits about 3/4 the depth into the hollow point, and tap it with a hammer until the lead expands. (More taps for more expansion). 

Then I size the slugs through a Lee sizing die .457 that I expanded/sanded & polished the inside to match the inside of my barrel bore. If you don't expand the slugs as much as I do, then you won't need the Lee press and sizing die. Just a few taps with the hammer on the punch expands the bottom several thousandth of an inch and acts as a gas check to seal the bore. Though sill .457" the front of the slug centers and rides the rifling.

 

[Asher]

That's a great idea, thank you. I will consider that although honestly it's a lot of trouble to go through when making slugs or even using ones I bought. I'm thinking I may see if xp airguns can make me a barrel for it that is suited for .457. I'd rather do that than go through all that effort with every slug. I do plan to make my own and my swage press can not go any bigger than .457 or .458.



Some are saying there are mods that increase its velocity but also make it use more pressure and get less shots per fill. That's a deal breaker. A selling point for me was its 3600 fill pressure and the six more or less full power shots on a fill that you get. I'd rather optimize velocity by messing with the diameter issue, either via barrel swap or fixing up the slugs.



I like this gun though

 

[Airgun-hobbyist]

That's a great idea, thank you. I will consider that although honestly it's a lot of trouble to go through when making slugs or even using ones I bought. I'm thinking I may see if xp airguns can make me a barrel for it that is suited for .457. I'd rather do that than go through all that effort with every slug. I do plan to make my own and my swage press can not go any bigger than .457 or .458.



Some are saying there are mods that increase its velocity but also make it use more pressure and get less shots per fill. That's a deal breaker. A selling point for me was its 3600 fill pressure and the six more or less full power shots on a fill that you get. I'd rather optimize velocity by messing with the diameter issue, either via barrel swap or fixing up the slugs.



I like this gun though

I like the gun as well. So much so that I looked into re-sleeving the existing barrel to a .452 as there are a lot of ammo choices in this size, along with a lot of room for polishing the bore. It is the easiest and least expensive way to go with the least amount of machining involved (to keep the cost down). But for now I will pound out and size the six hundred slugs I have from NSA and probably won't require much more than that once tuned properly. 

The next process will be to get the velocity up to the other guys' speeds. My 30" Challenger Bullpup only pushes the 240 grainers' to 840fps at 3100 psi. So now that the barrel and slugs are done I'll work on polishing up the moving parts within the valve system and porting and polishing the transition into the barrel to move the air efficiently.

 

[Asher]

Wow. I very much look forward to your results. Might lead the way for me. Yeah I got similar velocities with the 240 grains. A bit less actually. First three shots from a 3600 psi fill were around 815 fps, then the fourth was 798. Didnt measure after that. Got my compressor fixed though and plan to go and do more shooting and testing tomorrow. Just got a nice scope and high rings, and a nice case that fits it all.



Interested to see what results we can get just by optimizing the diameter but not getting the high power valve or springs. I'd be very happy with a gun that gets 6 400 FPE shots with 240 or 250 grains on only a 3600 psi fill. Considering my old bushbuck only got 2 high power shots , granted those were over 500 FPE, but you had to fill to a higher pressure too. And no magazine. I gotta say, I love having a 6 shot magazine on a bog bore. This feature alone had me considering a AAA slayer, the only other big bore I know of with such a feature. That's a $3000 gun in the version I would've wanted

 

[Asher]

So I did some testing today, the gun performed a little better than last time, maybe it was the cold IDK.



Take my pressure's apart from the first with a grain of salt, the guage is a bit hard to read precisely. I just started at a 3600 fill for reach 6 and here was the result. The 220s acted strange, the sequence doesnt makes sense when you expect a bell curve. It had rained a tiny bit so maybe a water drop was throwing some of my readings off IDK. I'm especially not sure about the 977 FPS reading, anyway here it is. I shot a few single loaded 290 grain slugs and wasnt really impressed with the numbers, they dont seem worth it. I added a 5 shot average FPE as the 6th shot was always substantially slower than the previous 5. Finally, a 6 shot group I made while sighting in at 50 yards which I'm relatively happy with. Using the 196 grains, which made the most energy anyway.

196 grains:
250 bar 905
230 bar 962
215 bar 966
195 bar 944
180 bar 916
150 bar 859
925.33 avg FPS
372.74 avg 6 shot FPE
383.51 avg 5 shot FPE

220 grains:
250 bar 842
235 bar 865
220 bar 977
200 bar 854
185 bar 926
155 bar 767
871.83 avg FPS
371.4 avg 6 shot FPE
389.48 avg 5 shot FPE

240 grains:
250 bar 833
240 bar 868
225 bar 845
210 bar 826
190 bar 786
165 bar 711
811.5 avg FPS
351.03 avg 6 shot FPE
368.63 avg 5 shot FPE

 

[Airgun-hobbyist]

Asher, that speed and group looks exactly like the speeds and groups I got today. I was not that impressed with the groups at all. At 50 yards I want them touching, especially with a slug nearly half an inch in diameter. I'm going to work on the crown and mount a tuner and muzzle brake first. If that doesn't work then I am going to reline the barrel.

 

[Asher]

I dont know much about messing with the crown, or barrel polishing, or moderators or barrel tuners. Tuners are like the weights you add at specific places to improve barrel harmonics right? Well, I look forward to your results, maybe I will follow your example. 



Are you saying your numbers were similar to mine even using your widened slugs? That is valuable info to me, as I'm considering a barrel swap for a true .457 one but only because I want to optimize velocity with .457 slugs, as these are the biggest I can make with my corbin s press swage setup.



It just occured to me. I should note the order the shots hit in next time I shoot a group. If the later and therefore slower slugs have more drop in the group, that could be accounted for to improve accuracy. You probably knew that, I feel dumb saying it

 

[Airgun-hobbyist]

I dont know much about messing with the crown, or barrel polishing, or moderators or barrel tuners. Tuners are like the weights you add at specific places to improve barrel harmonics right? Well, I look forward to your results, maybe I will follow your example. 



Are you saying your numbers were similar to mine even using your widened slugs? That is valuable info to me, as I'm considering a barrel swap for a true .457 one but only because I want to optimize velocity with .457 slugs, as these are the biggest I can make with my corbin s press swage setup.



It just occured to me. I should note the order the shots hit in next time I shoot a group. If the later and therefore slower slugs have more drop in the group, that could be accounted for to improve accuracy. You probably knew that, I feel dumb saying it

Asher, there are a few posts on the airgun forums and YouTube videos on DIY re-crowning and polishing of the bore. Be sure you are using the correct polishing method based on the type of bore (rifled versus smooth bore, and not choked for slugs versus choked for pellets) Practicing cutting crowns and polishing on any small diameter steel tube (aluminum or copper pipe will do too) first will gain yourself some skill and confidence.

Yes, I am getting very similar FPS numbers with the 240 grain slugs, though just a few feet slower because fitment is a bit tighter. 

Yes, looking at each hit individually will get you familiar with how each shot reacts to the loss of air pressure on an unregulated PCP. With your bell curve in FPS the hits should be low, high, low, lower, lower. You can set up your scope to see the hits as bullseye, high, bullseye, low, and lower. After becoming familiar with the hit pattern you can manually adjust the aim point accordingly to tighten up that group pattern for long range accuracy on target. For example, I hold over one additional MOA shooting at 200 yards with another unregulated PCP and it keeps a tight group this way.

 

[Asher]

If velocity didnt increase for you after widening the slugs, did it serve a purpose? Are they more accurate?

 

[Airgun-hobbyist]

If velocity didnt increase for you after widening the slugs, did it serve a purpose? Are they more accurate?

I did get slower speeds out of the sloppier ammo, so it did serve a purpose of sealing the bore so the fps is more consistent. A Hornady .457 round ball barely touched the rifling as it was. I will get you the numbers tomorrow from both the original swaged and the modified and sized when it is back together. Right now I am porting the valve so air flows into the transfer port in a smoother transition. Before it was two holes converging at a 90° and now it is radiused and opened up at the corners. This usually gives more consistent fps and shot spreads, but the ports were .470" so it may not gain a huge amount of speed. 

 

[Airgun-hobbyist]

Asher, after porting the unmodified NSA .457 240's had speeds of 820 FPS and the modified and sized slugs are topping out at over 900 FPS. There is a big difference in speed when there is a huge air gap around the slug.

 

[Asher]

So if I did a barrel swap for one that's better suited to .457 diameter and then ported, think I'd have similar results with .457 slugs? Who apart from xp airguns could I ask about a barrel swap? They arent being very responsive right now. 240 grains going 900 fps is a bit over 431 FPE. I'd be very happy with that. Curious if you have any 220s or 196s to widen and test, as those yielded higher energies for me, albeit unmodified

 

[Airgun-hobbyist]

With the modified/sized NSA 196 grain HP-DB slugs I get two consistent top speed shots right around 980 FPS, between 3100 & 2800 PSI. Now that there's a baseline for pressure where the valve opens without restriction, I'm hoping that a regulator could be fitted for a pressure of 2500 psi to get four to six consistent but slower shots... If anyone is knowledgeable in the realm of regulator's and the like please give some input in the new "Regulating a Big Bore" thread.

 

[Airgun-hobbyist]

So if I did a barrel swap for one that's better suited to .457 diameter and then ported, think I'd have similar results with .457 slugs? Who apart from xp airguns could I ask about a barrel swap? They arent being very responsive right now. 240 grains going 900 fps is a bit over 431 FPE. I'd be very happy with that. Curious if you have any 220s or 196s to widen and test, as those yielded higher energies for me, albeit unmodified

If you just ported the valve corners so the air flow up smoothly, added a hammer weight washer (which also adds spring tension), and tapered the barrel port holes, you would push those 240 gain slugs at 960 fps.

There is a decent amount of money invested in either a big bore barrel swap or re-line. Personally, I would look to any gunsmith shops that re-lines barrels and have them install a quality new liner, like a TJ's. That would probably be the least expensive way to go too. 

 

[Asher]

Finally got around to slugging my barrel. It is indeed a .461 just like everyone else. Bummer. I'm just gonna get a .458 die made and have the punch set up to make dish based slugs so that hopefully it acts a bit like a pellet skirt and helps make up the difference in diameter. I'll report back how it works out. 



The great thing about the Corbin press and die is I will be able to precisely change the length and therefore weight, and thus be able to hone in on exactly what weight slug is most efficient in terms of FPE. I know it's somewhere between 196 grains and 240 grains. This assumes stock configuration and not with washer rings and higher pressures used. Will report back on that too