As I slowly move forward with shooting slugs in my M3, I purchased a Huma slug power kit (not yet installed) and Im wondering if there are any downsides to shooting pellets with this kit installed and the barrel rotated to the slug "S" position? Im only shooting the FX or JSB 33.95 gr.
Tuning Any downside? of installing a slug power kit in a .25 M3 for pellets
- Thread starter beercanshot
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Honestly, a pin probe is not needed at all if you align your pellet probe properly. Some porting with Dremel may be needed. I think that pellet probe is much better than a pin probe consistency wise. It can seat the slug/pellet more precisely and repeatedly.
Again, please not chase every ad they throw on you. Always use your brain at first place.
Again, please not chase every ad they throw on you. Always use your brain at first place.
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Depending on your barrel length, reg pressures and weight of slug you decide to commit too, you might never need the slug kit. It might just cause you more aggravation. When you know your gun well enough to understand how each component in the kit will effect your gun, then you can make an educated decision about using all, some or none of it. Those kits definitely seem to appeal to guys who like buying trinkets and magic potions for their guns. The M3 is a plenty capable gun without adding do-dads.
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They should probably rename the slug power kits to "redline your gun kits". You can shoot light to midweight slugs just fine with a stock M3. I think the hammer spring spacers/weights are the most valuable part, but there is a tradeoff.
Slug kit components:
The mod offering the biggest power improvement is the hammer spring spacers/weights, but that comes at a cost of ease of switching between slugs and pellets. I can give a great example of what happens here on the same gun (700mm M3 in .30) with and without the spacers. Both guns are tuned to shoot FX 44.5gr hybrid slugs at 960-970fps.
To switch from slugs at ~960fps to pellets around ~880fps
My M3, reg at 150bar (NO hammer spring spacers)
Keith Gibson's M3, reg at 125bar (WITH hammer spring spacers)
Slug kit components:
- Valve return spring - not needed on the M3
- Pin probe
- Pro: may offer ~10-20fps gain
- Con: will only seat as deep as a pellet probe if you are using flat back slugs. Deep skirted pellets may be seated very shallow.
- Con: may not load projectiles as straight and smoothly as a pellet probe
- Con: may bend (depends on caliber and make/style of probe)
- Hammer spring spacer/weights, or replacement heavy hammer spring in the case of HUMA
- Pro: can run MUCH lower reg pressure and get same power output. This greatly increases potential power the gun can produce
- Con: May not be able to get the power low enough to shoot pellets, or at least easily switch between slugs and pellets.
The mod offering the biggest power improvement is the hammer spring spacers/weights, but that comes at a cost of ease of switching between slugs and pellets. I can give a great example of what happens here on the same gun (700mm M3 in .30) with and without the spacers. Both guns are tuned to shoot FX 44.5gr hybrid slugs at 960-970fps.
To switch from slugs at ~960fps to pellets around ~880fps
My M3, reg at 150bar (NO hammer spring spacers)
- turn macro wheel from 16 to 11
Keith Gibson's M3, reg at 125bar (WITH hammer spring spacers)
- turn macro wheel from 16 to 1
- turn in valve adjuster in by 1.5 turns
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That doesn't make sence to me can you explain in more detail? Does his gun have any porting done? Is it totally stock beside the spacers for the hammer? That is a big difference in reg pressure, as well limiting the valve travel.
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It makes perfect sense if you understand how the gun works. Gibson’s gun is hammering the valve much harder with the slug kits spacers/weights and has more dwell to control. So he has to make a bigger adjustment with the hammer wheel, and almost runs out of adjustment. Then has to limit valve travel even more by turning the valve knob in. He probably has to turn the valve in that far because he did run out of adjustment on the hammer wheel. So even at setting #1, he is still over driving the valve so he uses the valve knob as a band-aid fix. Those rubber balls in his valve knob might be taking a beating.
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I just realized we didn't answer your question on the using the 'S' slug port on the barrel. There doesn't seem to be any issue shooting pellets with the slug port. The thought is that you might be able to create a more efficient pellet tune with the round 'P' port, but the difference is probably small.
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The slug kit doesn’t really have too much down side besides shooting lighter pellets way too fast but that’s what the preload adjustment is for, M3 is superbly adjustable!
The pellet port is to be able to shoot pellets at slower speed highly consistently because the small TP has a physical limitation on how much air it lets through. The design of the pellet port is for people who really want that sub 10 fps spread to slowly drill out the TP as needed to tune for a specific ammo for least amount of ES. A lot of work and most won’t do it. For everyone else like me just shoot with slug port and adjust speed with all the adjustments you paid for on a M3.
The pellet port is to be able to shoot pellets at slower speed highly consistently because the small TP has a physical limitation on how much air it lets through. The design of the pellet port is for people who really want that sub 10 fps spread to slowly drill out the TP as needed to tune for a specific ammo for least amount of ES. A lot of work and most won’t do it. For everyone else like me just shoot with slug port and adjust speed with all the adjustments you paid for on a M3.
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TDK and Vetmx are exactly right. If you tune your gun for Max power, you will likely lose adjustability to go low or go between pellets and slugs. There are a number of things at play and it there are a lot of combinations possible. Transfer port, slug kit, springs hammer weights, spacers, probes etc. I have a question along these lines. If I do nothing to a stock gun, (it's a .30, so there is no factory slug port (although I could install a Huma), would installing ONLY a Huma tuning spring do anything for my power?
I am personally not a fan of the light spring. It’s one of those mods that comes at a price. You can’t accuse them of false advertising because that weak spring is going to make your valve think there almost isn’t any spring in there at all so your dwell will be much longer. Now, at what cost is where you have to figure out if a few FPS is worth it. With that lame spring in there yes, you’re taking bigger gulps of air. But when you start to tighten your valve knob down to get the gun to behave, now your C1 is blowing through the week springs travel and you’re smacking your C1 off the knob piston. Now your gun is making a sound that it shouldn’t because you’re relying on the knob piston and rubber balls to almost dead stop your valve. So you go ahead and do it anyway because you are happy with your result. The gun now goes tink every time you shoot it but you like what your chronograph is telling you. But it might not be that much faster and now you have induced another wear item, the rubber balls. It might take 300 or maybe 900 shots but your wonderful tune will slowly fall apart as those rubber balls are beaten into submission. Leave the stock spring in the gun. There are good mods for Impacts for guys to blow money on. Hot rod items are not necessary.
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Stock spring gave me more consistent fps. Heavy hammer really ups the power. I found that the heavy hammer needs higher reg pressure and lowering fps gun starts to sound harsh. Heavy slugs and high reg pressure makes my 30 m3 kick a little.
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One more question. What about the Huma tuning hammer spring in say an FX Maverick? There is no valve adjuster in which to put a lighter valve spring. It is said by some it tinks in their ear even without the Huma tuning hammer spring.
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An Impact tink and a Maverick tink are two different things. With a Maverick or Impact, once you start getting into reg pressures that the stock hammer springs start running out of gas, it’s time to either add weight, more spring, or both. Then shoot 10 million pellets or slugs as you test. With a gun like a Maverick that can’t control the valve, you want just enough spring and weight to get the velocity you want and have the gun feeling it’s best. An over sprung or heavy hammer gun is a blubbery thing.
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