Crown tuning for slugs

[Eamon]

I'm new to tuning and have a quick question. I am using NSA slugs and the two that show the most potential are the 36.2 hpfb and the 38.5 fbhp. I have tried VN and used the NSA sample pack every other slug was all over the place or a large group that just would not work.

I'm at 159 bar on the reg going average 865 fps. I "think" that the tune is most likely around there with some more work. So my question is where is the place to stop on top of reg pressure? I just don't want to get in the problem zone.

Thank you in advance for any help.

Eamon 

 

[Jayson]

Eamon,

what version of crown do you have? And do you have a heavy hammer mod? Barrel length also

 

[stoti]

Hey Eamon, how's it going? Where do you have your gun's HS preload set? You can gain quite a bit of velocity by maxing it out too and then backing it off when fine tuning. Is it a 600mm liner? Most all of these NSA slugs will shoot great out of the FX liners. If you test them and they don't work, don't fret. It's probably just because they don't like the particular velocity at which you're shooting them. Don't give up on the lighter ones because they didn't show promise on your initial testing. It can at times be a long, drawn out process. Believe me, I've had to just "walk away" on more than one occasion. Stick with it, these will all shoot. I've shot all of these slugs and many not offered for Nick, they all shoot if you tune the gun correctly... Some better than others of course! Well, I take that back, I gave up on the dimple nosed slugs! The reason I'm telling you this is because if you choose a lighter slug, you'll be able to shoot it faster and most all of these slugs like to be shot between 920-980fps. Some are fine over 1000fps and since they're spin stabilized, that's a good thing. The sample pack has both .249" and .250" slugs, make sure to give both diameters a fair look. I have had great luck with the 29gr slugs(.249"), the 33.5, the 36.2 and the 38.5(all .250"). However, I had to add power tune parts to my Impact to really get the 36.2 and 38.5 going at the velocity where they really shot great. Lubing slugs is usually beneficial too. There are so many variables when testing slugs, one of the most important things to remember is to isolate each variable by changing only one thing with your gun at a time while tuning it or you'll never know what's really going on. Lastly, if they're shooting for you at 865fps and you like the results, that's great, stick with it. I'm certainly not saying that won't work or telling you what to do, just sharing my experiences and trying to help. Happy Thanksgiving! 

Stoti

Here are the most recent velocities where I've had the best luck with some of these slugs...

29gr. 960fps

33.5gr 945-950fps

36.2gr 940-945fps

38.5 940-950fps

 

[Eamon]

Jason and Stoti,

Thank you for your reply. I will do my best to answer your questions in some kind of order.

My Crown, I think would be called Gen 2 it has the AMP reg.

No hammer spring mod, the hs is maxed, but I can turn the hs wheel.

600 mm barrel

Also, where do I find the hs weight kit? I know some members here sell them I just don't know whom to ask.

Again thank you so much guys for all of the information you provided!

Eamon

 

[stoti]

Eamon,

Just post a WTB in the classifieds. The hammer weights are fairly common. I think there was actually a listing just a couple of days ago for a power tune kit or parts. I’ll look at home, I might have a spare in one of my shooting bags. If I do, you can have it. As far as your initial question about regulator pressure... I’d feel comfortable going up to 170-175 BAR, some will probably tell you even higher. Just my opinion. Without the hammer weight though, most likely won’t see any gains at all. 


If you have any more questions or need any help at all, feel free to private message me, I’ll certainly help if I can. It’s time consuming and not as simple as some would have you think but when it all comes together... Awesome! Unless you get lucky and your gun shoots well straight out of the gate with the chosen slug, it’s going to take time and a little effort. Getting slugs to shoot out of the gate almost never happens! Good luck!

Stoti