I bought a used .25 with slug liner A, I was told. I want to tune it to shoot the NSA 29.5gr slug. The gun came to me with the reg set at 165 bar, which seems high to me. I do not know if I have the AMP regulator, I think it’s the previous generation regulator. Where would you set the regulator to start the tune?
Tuning FX Impact MKII Power Plenum reg setting
- Thread starter cmatera
- Start date
Cmatera,
When I first got my MK2 in .25 (it’s now a .30 Cal beast, so different tune) the reg was set at 105 Bar. 165 seems rather high. I would reduce it to maybe 120-125 and start from there.
Chris
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165 bar is way too high. I shoot the .25 NSA 43.5 grain at about 900 FPS and my reg is at 135 bar. PP plus pin probe and lighter valve spring plus Ernest transfer port, slug A liner. Hammer spring is stock and no hammer weights.
So to shoot those very lightweight slugs I'd look at about 110 to 115 bar to start. But, I'm not sure the Slug A will be accurate with .249" diameter slugs. I think with the Slug A you'll want to shoot at least 34 grain, if not more.
So to shoot those very lightweight slugs I'd look at about 110 to 115 bar to start. But, I'm not sure the Slug A will be accurate with .249" diameter slugs. I think with the Slug A you'll want to shoot at least 34 grain, if not more.
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I had the same setup but my gun prefers the 36.2a160bar shooting 910-920fps then. But now with an enlarged tp and probe power plenum and slug power kit @110bar it’s tuned to 940-950 on max , but I shoot daily in my back yard and I have been shooting on min power @870-880 with great results and more shots! Good luck on what ever you decided on
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Supposedly, the gun started out as a .22 700mm, and the .25 700mm added later. Both have slug A liners. No pin probes, probably no slug power kits The .22 only has a pellet transfer port. Maybe i should pull the barrel and see what kind of transfer port is on the more recent .25 barrel. Another member here told me he has a simiilar setup and shoots the 29.5gr with his reg about 115 and the magic speed for him is 950fps. I do think I’ll lower the reg. Thank you for the help.
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I'm with Centercut and 8thman on this. My .25 700 Slug A loved the 33.5, 36, 36.2, 38.5 NSA slugs and the 34 VK slugs just as well. Although it did OK it did not do as well with the lighter slugs that were less than .250 diameter. I had my reg set at about 135bar and shot them with excellent precision at different speeds from 740fps all the way up to 960fps. By excellent precision we are talking about groups of .5 inches at 100 yards, often as not, in good conditions. No pin probes nor slug kits involved.
Scroll down for the targets
https://www.airgunnation.com/topic/installed-my-new-700mm-slug-liner-on-my-impact-and-started-tuning/?referrer=1
Scroll down for the targets
https://www.airgunnation.com/topic/installed-my-new-700mm-slug-liner-on-my-impact-and-started-tuning/?referrer=1
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I do have some heavier slugs I could try 36-43 gr NSA, some Griffins and some AVS. Just because the guy included 304 FX Hybrid 26gr, doesn’t mean that’s what he was shooting. I do think the reg will need to come down some though, so somewhere in the 110-135 bar range is where I’ll probably shoot for.
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I can’t be of great help because I’m only using a 600mm barrel but my .25 is completely stock and my reg is at 130b for 26gr slugs. Like others have eluded to, probably just start out at 115b with the 29gr. You’re going to have to climb the reg ladder with every slug weight you test but I agree that the 165b starting point is too high. Even with a gun with no mods. Brace yourself for a lot of shooting but hopefully you can get lucky an find a setting rather quickly. Go slow so you don’t have to look back and second guess that a setting from a couple days ago may have been the one if you just would have spent more time on it.
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One last question. I know when turning down the reg, I have to remove the bottle first, then get the air out of the plenum. I watched a YT vid by AoA where they turned the macro power wheel to min and dry fired to drain the plenum. I also know that E Rowe is not a proponent of the firing to drain method, but, if I unscrew the adjustment CCW too far, I can blow the o-ring on the adjuster. I do not think this gun has the AMP reg. Any thoughts on the best way to drain the air from the plenum so I can turn down the reg?
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Your gun is a MKII so you have an AMP reg unless the previous owner swapped in a Huma. I know guys say you can turn down the reg a 1/4 turn then dry fire, then do it again until you get to the lower setting you’re looking for but I’m too paranoid about my reg seat. Especially if my gun is not creeping, I just want to take good care of it so I take off my bottle and turn the reg screw out a little and the plenum will drain. If I had to drop my reg just 5b, I would probably do the slight turn and dry fire method. But since you have to drop from 165 down to 115, just degas it.
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I do the turn and burn method but good advice here. 2+ years doing that method and no issues but a big drop like that why not degas. And yeah 165 is way high.
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Cmatera, I may have miss it. But I didnt see where you said if your gun was the mkii or a ppmkii. If your gun is the smaller plenum and valve mkii model. Yes, your regular set point will be much higher. Maybe even as high as 165. If your gun is a early model with the smaller valve and not the latter MKII model’s , that could be a factor of why the high press too
Some of the early barrels had a small transfer port as well. That would require a higher pressure to push the speeds your looking for. Maybe your gauge of off a little How many’s shoots are you getting per fill? Is you gun have the 480cc bottle?
Post a pick of your gun, let’s see what you got
Some of the early barrels had a small transfer port as well. That would require a higher pressure to push the speeds your looking for. Maybe your gauge of off a little How many’s shoots are you getting per fill? Is you gun have the 480cc bottle?
Post a pick of your gun, let’s see what you got
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It is an MKII with the Power Plenum. Since several members said the .249 dia slugs don't shoot as accurately as the larger diameter slug, I figured I'd go with the 36.2gr NSA. Of course I have hundreds of slugs, but no 36.2' NSA. I did have .254 AVS 36gr cup base slugs so I started out with those. The reg is now a 140, and with the macro wheel at MAX, I fired 19 shots with an ES of 2, and an SD of .998, so I think that's a good starting point in testing for accuracy.
All I can say is I only wish I had made a video of it. The only thing I can liken it unto is to anyone familiar with the Married With Children TV episode of when Al Bundy and Mr. D'Arcy put up the satellite dish.
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That sounds like a nice tight tune. Just based on that tune, I would say that it does not have the slug kit installed in it. The ES would run slightly higher with a slug kit.
I have my MKII .30 cal sniper set at 135 bar pushing 90 FPE with ease. I do have the slug kit and dual Huma transfer port installed though.
I have my MKII .30 cal sniper set at 135 bar pushing 90 FPE with ease. I do have the slug kit and dual Huma transfer port installed though.
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That does indeed sound like a nice tune. These guns are really fantastic if you treat them right, and are capable of remarkable performance. I too have my MKII Converted to .30 cal 700mm barrel. With my reg at 125 I get 899 FPS using the JSB 50.15 grain pellets. That’s 90 FPE with an extreme spread of 5 FPS across 10 shots. By the way, I used Triggertreat’s advice on tuning from an earlier post to help get there!
Chris
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Thanks! I have taken the 50.15gr to 115 FPE so far on 150 bar. I have never tried max set point (170 bar) yet. I don't think an airgun should be stressed to max if seeking best overall performance. I have not shot any slugs in .30 cal yet though.
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