Shooting and Tuning AEA Challenger .30 Bullpup

[Pellethuntr]

Long story shot I decided a couple months ago that I needed to add a .30 to the safe. After talking with a whole bunch of people on here and other places I landed on a regulated Challenger Bullpup with the heavy hammer spring. I picked one up on the used market and got right into it.

Today I shaved and polished the sear and trigger. I highly recommend taking the time to watch the YouTube tutorials on how to do that. I unfortunately don't have a trigger pull scale but I think it is on par with my Texan now. I had ordered a couple boxes of the NSA 61 grain .303 slugs so I proceeded to set the gun up for them. I have them tuned to shoot two mags at 950fps average from 4350 psi down to 3000 psi with the stock regulator setting (I believe that to be around 2700-2800psi). These are the first two groups I shot at 50 yards this afternoon. Not too bad but there is definitely some room for improvement!

I plan to take this gun out to 100-150 yards in the next few weeks as I have time.

Edit: My power wheel is set at the 10 o'clock postion for anyone wondering

[Pellethuntr]

IMO this gun is capable of hole on hole groups at 50 yards and MOA at 100 yards. So I slugged my barrel last night and MIC'ed the bore at .3045". No wonder my .303 slugs are only giving me mediocre results!

I am currently in talk with a few different small time slug manufacturers about having some .304 and .305 diameter slugs made.

In the mean time I figured I had nothing to loose by knurling some of the .303 NSA slugs that I already had. I sandwich the slugs between a coarse file and a pine board and roll the slug back and for a few times. The resulting "knurls" measure at .309 and is a bit snug in the mag and it takes a little bit of force to get it in the barrel. But boy did it improve my groups!

I think I am on the right track here. I will keep updating this thread with information as I get some larger diameter slugs to try.

[oneshot61]

Nice work. I’ve knurled several of my slugs for different guns and it definitely tightened up my groups… very good power out of that gun.

[Pellethuntr]

Nice work. I’ve knurled several of my slugs for different guns and it definitely tightened up my groups… very good power out of that gun.

There is a lot of power potential with these guns. I think that a 120-150 grain slug would be ideal but unfortunately 80 grains is about all that can be stuffed into the mag. I bought this gun to use the multi shot feature so I am not real inclined to give that up.

The custom slugs should be here Monday and I will test them asap. We have high hopes for MOA accuracy.

[Pellethuntr]

A little update on where I am at with this gun. I had a custom bullet maker send me some slugs that started out at .300 and were put in a knurling die. He sent me a bunch of .308 .309 and .310 slugs to test. All the slugs he sent are 69.8 grains and 0.462" long flat nose hollow base. This gun seems to prefer the .308 diameter slugs.

I shot this 5 shot group at 50 yards today. 4000psi fill and the gun is tuned to shoot these at 960fps. Unfortunately I got really sunburnt while on vacation this past week and my back and shoulders are in a lot of pain, I noticed visible shaking in my scope while shooting. I think I can do better when I get things all healed up! I didn't measure the group but I would say it's right at 3/4 of an inch. Making progress!

[Back_Roads]

 About on par with the groups I am getting with my standard 

[Pellethuntr]

About on par with the groups I am getting with my standard 

Thanks for the info!

I can't believe just how over bore this barrel is!

[fixit]

About on par with the groups I am getting with my standard 

Thanks for the info!

I can't believe just how over bore this barrel is!

That lines up... powder burners  have to slug the bores of their rifles to figure where to start when they go to cast bullets. No reason air power would be any different. I like the results you're getting!

[Pellethuntr]

Thanks for the info!

I can't believe just how over bore this barrel is!

That lines up... powder burners  have to slug the bores of their rifles to figure where to start when they go to cast bullets. No reason air power would be any different. I like the results you're getting!

I just realized I forgot to add an important update to this thread. Last week I removed the barrel from the rifle so I could get a good look at the rifling and inspect it for any build up or pitting. The bore looked squeaky clean which was not as surprise as I had just cleaned it a few days prior. I'm told that slugging a barrel and measuring the "slug" is the most accurate way to measure bore but on a whim I thought I should take my calipers and measure each individual bore/land groove. What I found was that the lands all measured at around 0.300" but the grooves measured 0.308-0.309" and every where in between. Not saying calipers are a good way to measure a bore but that is what sent me on the path to shooting the much larger diameter slugs.

[Scotchmo]

Your measurements of .30 bore and .308 grooves indicate a .308 caliber.

NSA makes 65gr and 85gr .308 slugs.

https://nielsenspecialtyammo.com/collections/308-caliber/products/65-gr-hp-db-308-cal

Do you know your twist rate?

[Back_Roads]

 IIR AEA now offers various cal. sized barrels now, eg .50 .510, 45 457 I am not sure about that in .30 but could happen just in normal Chinese production also.

[Pellethuntr]

Your measurements of .30 bore and .308 grooves indicate a .308 caliber.

NSA makes 65gr and 85gr .308 slugs.

https://nielsenspecialtyammo.com/collections/308-caliber/products/65-gr-hp-db-308-cal

Do you know your twist rate?

I am currently shooting custom tailored slugs from Rich Briscoe, his company name is BARS. He does custom slug orders at a very reasonable price. I told him the shape, diameter and the over all length that I wanted and he sent me the slug I detailed above. 70 grains is about the maximum weight/length that will fit in the mag on this gun. Which is too bad IMO as a 100-120 grain slug would be ideal for tapping into the available power. As I said before I bought the gun for the mag feature so I don't plan on shooting anything that doesn't fit in the mag. I may try the 65 grain NSA slugs at some point but I don't see a need to at this time.

The twist rate is 1:26

[Pellethuntr]

IIR AEA now offers various cal. sized barrels now, eg .50 .510, 45 457 I am not sure about that in .30 but could happen just in normal Chinese production also.

I have no doubt that this barrel is a product of Chinese manufacturing QC issues. I bought the gun used for a very reasonable price. Judging by the amount of different ammo the previous owner sent with it he never found something that shot well and he got frustrated. Which is totally understandable if you don't have the tools or knowledge to measure and find out what you are dealing with.