FX Impact/Maverick Long Distance SLUG Caliber ? And Why?

Regardless of size and weight BC is the definitive measurement of how the environmental variables affect the projectile. Bigger and heavier isn’t always better. Good example: I can out shoot .25 JSB heavy 34 grain pellets with 12.5 grain 177 slug that has 20-30% better BC. Especially in the wind even though it is less than half the weight. FPE is simply the measurement/calculation of speed and mass, BC dictates down range/remaining speed.


to answer your question, find the projectile that has highest BC at highest speed your gun can shoot. Both heavier .22 and .25 slugs have very high BC relatively speaking, personally I’m sticking with .25 slugs for now. For now .22 has better slug selection but I prefer .25 because I can get similar weight slugs to shoot faster thanks to bigger bore/transfer port size. I got 29 grain .25 slugs screaming at 1045fps with only 120 bars Reg pressure in my impact MK2PP.


Hope that helps. 

Can’t remember where i saw it but it was about ebr and best calibers and it was claimed that 25.4 gr 22 cal was the hot ticket but many shot 25 cal 33.9 and many others were shooting 44 gr 30 cal. So i would say depends on your gun and the caliber it likes best. 1 of those 3 should put you in the ballpark if you do your part

/\ +1 on qball's explanation.

I'm curious too. Do 177 slugs make a pop sound .

Even at 300 yards, .22 and .30 is still close. So it comes down to your plan for the gun, if punching paper at long range, then I will go for 22. If putting down a coyote at 100 yrd (any longer you risk unethical shot) is a necessity then I'll go .30.

qBall what are you using to shoot those 12.5 grain .177 slugs what speeds also ? Very curious on that little stinger setup.

Makes sense I see so many guys shooting 30s a long way maybe just for the power a slap not sure why...

Jay

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177 slugs are simply AWESOME! Very underrated and still got a lot of room to improve. But the limitation is bore size so slugs can't get too long/heavy to get really high BC, airguns simply don't have the explosive power needed for a 30 grain 177 slug even at 160 bar reg pressure. Maybe one day we might have a 800mm 177 slug barrel? I'll be willing to try that on my impact. 



I shot 177 NSA 12.5 grain slugs out of my FX dream-tac compact and crown MK2 and even my PP700 when it had a custom 16 inch barrel but didn't do a ton of test on the PP700. With my Crown MK2 I shot 760 FPS from the 300mm barrel and about 940FPS out of the 500mm barrel. Both very accurate and easily out shot 34 grain JSB heavy pellets. Still not that great in comparison to 29 grain NSA with BC of 0.08 flying at 1040 FPS but with a little skill easy MOA group at 100 still. Sadly I didn't do any groups at 100 yards with the 300mm barrel but got easy 1/2 inch group at 50 yards, although I did messed up the tune by trying to improve it. Slugs in short barrels are difficult to tune for. The 500mm barrel shot the 12.5 grain 940FPS is easy MOA at 100 yards if condition and/or skill permits. 

Regardless of size and weight BC is the definitive measurement of how the environmental variables affect the projectile. Bigger and heavier isn’t always better. Good example: I can out shoot .25 JSB heavy 34 grain pellets with 12.5 grain 177 slug that has 20-30% better BC. Especially in the wind even though it is less than half the weight. FPE is simply the measurement/calculation of speed and mass, BC dictates down range/remaining speed.


to answer your question, find the projectile that has highest BC at highest speed your gun can shoot. Both heavier .22 and .25 slugs have very high BC relatively speaking, personally I’m sticking with .25 slugs for now. For now .22 has better slug selection but I prefer .25 because I can get similar weight slugs to shoot faster thanks to bigger bore/transfer port size. I got 29 grain .25 slugs screaming at 1045fps with only 120 bars Reg pressure in my impact MK2PP.


Hope that helps. 


what length, what barrel, what twist, what brand slug ?? How many mags on full bottle?

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@bertman77mk2: I'm shooting FX barrels so twist rate is 18 which is definitely slow but enough for 12.5 to work well enough. I wouldn't bother with the 15 grain as the twist rate is way too slow to waste time and money on. Hoping one day FX will come out with at 1:12 177 slug barrel, that would be dope! maybe even 1:11 or 1:10 in 800mm.....I can dream right? I've standardized on NSA slugs and honestly don't remember how many mags, I only fill to about 230 bars and get about 3-4 mags with 177/22 and 2-3 mags with .25(for now, need a lot more tuning)....don't quite remember but enough shots to not get annoyed with filling up and be tethered instead. I rather tune my gun to be on the more efficient side, when over powering the barrel and creating too much muzzle blast the lowly airgun subsonic slugs can easily get destabilized and create in consistency so I rather shoot a little slower than trying to get max speed. 



@jaydog: Completely agree with the assessment, speed is good but BC is EVERYTHING. I don't have much advise on the 177 slugs except try the 12.5 grain until FX get their act together and come out with a 1:12 slug barrel. based on online twist rate/stability calculator the 15 grain need minimum 1:16. The 177 slugs use less air compared to my .25 slugs BUT not massively less, goes back to the efficiency lost thanks to the small bore. Both 177 and 22 at 200 yards will be challenging but good enough to get on paper and print a descent group with good condition. For the most part I'm shooting the .25 slugs at 200-300 yards and .177 and .22 slugs for 200 and closer, my crown MK2 can't really push the heavier .22 slugs(30+ grains) that well so sticking to the 23 grain but will try 27.5 grain one of these days. Also want to mention try to find an efficient tune, little 177 slugs can be destabilized quite easily. 

The lowly .22 has won at one of the 100 yard benchrest competitions so it can do that with the right shooter on the right day. But the .25 and .30 are the usual winners and do it far more consistently.

Pellet BC matters but evidently by looking at the statistics of winning calibers in competition it is not the king of 100 yard shooting.

With my 700mm .25 slug A liner I shot mostly <MOA, with NSA and VK slugs, at 100 yards for several months. It also did well at 200 yards although I shot no paper instead I shot paint cans which I often hit three and four in a row when I got my wind calculations right. Now that I have my M3 700mm in .30 I shot <MOA on my second outing, with JSB 44.75 pellets, after sighting in my scope and with very little tuning.

So, it looks to me more like a pick your poison and get good with it sort of thing if you are shooting paper. However, if you are shooting pests or dinner then your choice should be something with the knockdown power you need, for your individual prey, at your specific ranges.

Depends you hunting or shooting targets? What are you hunting if so? .22 slug on targets and small prey. .25 cal slugs or my favorite .30 cal slugs on larger prey.

I’d suggest you go the .25 cal. The slugs are cheap and the 34.9 NSA B.C. .11 is very goid and accurate in my impact superior liner and my Uragun. 


the new H&N 32 and 34 grain slugs are amazing in my Uragun…I’m going to test in impact soon. 

before you start winding out your guns for max power, consider trying speeds at 840 fps and working your way up. All this stuff you hear about needing high speed should be verified not assumed. 
my Uraguns shoots moa way past 100 yards at 895 fps and my impact is close behind. Reg pressure is about 135. I can easily hit 8” steel plates out to 300 in moderate wind. 


it’s difficult to get the heavy .22’ slugs shooting at 1000 fps without running the reg upto or past 170 with an impact mkII 

hard on the gun and kills shot count. The impact mkiii may be the better choice If you need all the extra speed 

Brad Salt Lake

I know it’s not relevant to the slug aspect of this thread but it is to the .177 side of things….a wise man once told me if your barrel likes the 16g .177 beasts then they behave very well at long distance and are very similar to a slug in shape. 

Quote from above:

“The lowly .22 has won at one of the 100 yard benchrest competitions so it can do that with the right shooter on the right day. But the .25 and .30 are the usual winners and do it far more consistently”.

Not necessarily true. The lowly .22 has won the past THREE Extreme Benchrest Competitions in a row…. Seems consistent to me. Also had some of the highest scores at RMAC 2021. 

The Uragun shoots H& N 21 grains slugs at 840fps (untuned from factory) as or more accurate than any airgun I’ve ever shot. 


191 yards last spring ( ground squirrel in alfalfa field) my truck is in the background : )

im sending the gun to Derrick Wall for a tune with .22 RD’s.

One thing that stuck out to me regarding wind came from one of the RMAC shooters (it was on AEAC's interviews). He said that the more wind there was, the slower he shot the pellets. I believe he was inferring that he would be ok with slightly more drift to get more stability. He believes that wind destabilizes pellets more as they travel faster. I do wonder if some slug shapes can affect that like pellets would. 

According to StrelokPro and ChairGun… shooting slugs slower ( within reason) lessens wind drift not increase. ( I don’t know what the reality is)
For example:

Slugs @ 100 yards

I shoot A Uragun with 21 grain .22 H&N slugs at 840. 
-With a 10mph right angle crosswind… the wind drift shows1.6 Mils

-with the same setup shooting 1050 fps the wind drift shows as 1.9 mils.

Pellets are quite different but are pretty close fast or slow at 100, but at 200 yards the fast pellet has much less wind drift. My guess is that wind drift increases with increased time in flight…and due to the rapid deceleration.

id love to know real world results.