Accuracy comparison: FX Crown MK2 w/380mm vs MK1 w/700mm

Wiely,

It took a lot of trial and error to get both guns where they are now, so I'm gonna leave them as-is for a while. I don't think that there is much difference in how they shoot between the MK1 and MK2 Crowns. The MK2 has more power to shoot at higher fps, but from my testing, slower(880-890fps) was MUCH more accurate than faster(up to 945 fps) and was much "tamer" to shoot with the 700mm Superior Heavy barrel. The chassis, however, is MUCH more accurate, easier to shoot, and heavier than the synthetic stock and worth ever penny!



Thanks, MoeHofer!



Thanks, Mike. That's a good idea to shoot BR cards and keep a running record. I'd like to know how it holds up over time. Accuracy can be so... fleeting.

Phil

Smok3y,

The "common wisdom" is the faster the better for slugs and it seems like most people are trying to shoot them close to 1000fps. Admittedly, higher speeds may be more desirable, but if they aren't accurate then they aren't much good. I have found good accuracy at slower speeds, but still fast enough to prevent getting blown all over the place at longer distances like pellets when its windy. Plus, shooting them slower tames the gun down and makes it much more pleasant to shoot(and saves air).

The JSB Knockouts in .217 shot horribly when I tried to push them hard. The .216 shot horribly at any speed. Maybe try ordering sampler packs of slugs, from NSA or H&N too. Don't be afraid to experiment with different weights, diameters, or speeds. Different slugs do better in different barrels/lengths at different speeds.

Good luck

Spray1Mark,

I have edited the original post to include which liners are being used. The 380mm is a Superior and the 700mm is a Superior Heavy. I have not been able to obtain a Superior in 700mm yet. The 700 Superior liner would probably? perform better shooting slugs at higher speed than the liners I have tried.

I usually shoot pellets when its not too windy, but I wanted to try to have a setup that I could use in the wind at longer distances. So, I tried many different slugs(.2165, .2175, .218 NSA 17-30g; H&N 21-27g, FX Hybrids) at many different speeds through both the MK1 and MK2 using 700mm STX pellet A, slug A, and Superior Heavy liners, usually trying to shoot them as fast as possible(up to 1000 fps). I wasn't able to get any consistent accuracy with any of thing until I started slowing them down and reached the setup using the .217 KOs @ 890fps in the 700mm Superior Heavy barrel with DonnyFL Tanto(better accuracy than other moderators on this barrel). 

Like you, I think the 700mm is a broomstick, so I tried all previously mentioned slugs at various speeds through the 380mm barrel(much better for plinking or pesting) in the synthetic stock(much lighter than the chassis). The best tune I have been able to come up with for the 380mm Superior barrel is the .217 KOs at 805 fps(which I think has excellent accuracy considering its shooting slugs through a 380mm barrel).

I don't see much difference in the way the MK2 shoots compared to the MK1. The MK2 has a little more "horsepower" so I used it on the shorter 380mm barrel to have the ability to push pellets/slugs a little faster, while using the MK1 on the longer 700mm barrel(easier to achieve higher fps using less "horsepower"), but at the slower speeds I've settled in on, I could use them interchangably.

The BIG difference in performance is that Chassis! So solid, so forgiving, so "quiet-shooting", it's a LOT easier to shoot accurately.

Later, I will post some of my testing targets to show how poor the accuracy was with MK2/700mm combo at higher speeds.

Wiely and Spray1Mark,

If you're interested in a MK1 vs MK2 power difference with the 700mm barrel shooting .217 JSB 26.38g KOs at their maximum tune:

MK1- 905 fps (max recorded fps w/ FX chrono)

MK2- 977 fps (max recorded fps w/ FX chrono)

Now the MK1 is 2 and half years old, and the MK2 new, but that should give you an idea.

yenniedn and Ranchibi,

Thanks for the kind words!

Smok3y,

I'm like you, I'd MUCH rather shoot the 18g and King pellets. I just wanted to find a way to target shoot and pest at longer distances (more than 75yds) when it's windy. Also like you, I always heard they need to be shot really fast, so that's all I tried- fast and faster. I hadn't seen or heard of anybody having good luck at longer distances shooting them slower, but then I started experimenting and found some good accuracy at longer distances shooting them slower. I certainly don't know all the ins-and-outs of shooting slugs, but I thought it may be interesting for people to know that you don't HAVE to shoot them REALLY fast. 

From my experience, the slug diameter really has to match up with your barrel. If a slug is hard to chamber(noticable resistance), it's usually gonna open up your groups, drop your POI, and shoot slower. Conversely, if the slug diameter is too small(no resistance chambering), they will shoot fast and spray all over the place. Pellets are much easier!

Glad you're enjoying your Chassis as well. That thing is SWEEEET!

Regards, Phil

Thanks, L.Leon. When the wind comes from a certain direction, it "bounces" off the house, shed, and trees to swirl on one of my shooting lanes. Wind flags 30 yards apart go full out in different directions, then go the same direction, then switch to opposite directions, then... I obviously don't try to shoot pellets at long range in those conditions; thus the "heavier" slugs



Berto1,

I shot 15 five shot groups on each target. I'm not sure I remember how many shots per fill, but I THINK I was getting about 45-50 shots per fill using the MK2(regulator set to ~165 bar) and over 75 shots with the MK1( reg set to ~140 bar). I remember that I had to stop and refill the MK2/380mm barrel target, but I shot the whole MK1/700mm barrel target without refilling.

P.S.- Only way that I got that kind of accuracy out of the .217 KO slugs was to sort them by diameter. Previously in testing, I'd found that a lot of them were too wide and wouldn't chamber smoothly. These wider ones would be slower, spiral badly, and open up the group sizes tremendously. Fyi