Tuning FX Impact M3 35 cal power destiny

[7Green]

That is awesome. I am sitting on 3 boxes of .357 93 grainers, 2 boxes of 93 grain .356's and a box each of 79 grain in .357 and .356.

I haven't done any sort of accuracy tests with the 79 grainers. I only did speed tests, which were right at 930fps.

I still think there may be another 10 to 20 fps in the gun if I can open the reg above 165 to 168 bar. I wonder at what point the hammer spring has induced as much energy as it can into the hammer's weight. 

I want to figure out a way to make a 33 to 35 grain combined hammer assembly that allows full adjustability of the micro dial. I think the tungsten insert would do it, but drilling it out is another issue. Every part made of brass might too, or a lead insert.

Either way, I have some tinkering to do.

Good luck with the squirrel hunt.

 

[TMH]

Maybe a bit off topic, but a little word of warning to M3 .35 cal owners (and maybe Mk II guns as well?).

I recently removed the shroud from my .35 M3 for the first time, and when I was replacing it and snugging it back up - SNAP!

The liner lock had failed. FX doesn't give torque specs on this, nor even a caution. Maybe my gun had a defective liner lock? Maybe the liner lock is thinner on the .35 cal guns due to their larger caliber and a little larger O.D. of the liner? But having a gun under warranty and no access to a good local machine shop, I had to send the barrel assembly back to FX for repair.

They are handling it as a warranty repair - kudos to FX. But just be a little cautious when snugging the shroud back onto the gun. I suggest a very light snugging only after this event.

 

[ram2jeep]

thanks for the heads up @TMH...

 

[ram2jeep]

Got the email earlier today that AGD has .35 JSB pellets in stock. Get them while their hot!!

 

[mtndragon]

Thanks for the head's up. I went with Pyramyd, as they're cheaper with the 3+1 deal there.

Unfortunately, FedEx still has my .35 M3. I am at my wits end with that dysfunctional outfit. They claim that my home is still in the evacuation zone, even though it has not been since last Saturday. I have called the warehouse in Sparks and corporate. I've provided links to the sheriff's website showing them and they still say that can't deliver. It would seem that all of FedEx shares one brain cell and pass it about. I am really wishing FX used UPS. FedEx has been holding my rifle for longer than FX took to repair it. Ugggh.



At least I'll have ammo some day when I get it back.

 

[ram2jeep]

@mtndragon sorry to hear about your Fedex difficulties and glad you were able to grab those pellets. I received my M3 back this past Sunday but haven't had a chance to get to the range. Have done some speed test and FX tuned it for the pellets at a fps of 875; has been staying there all week. 
Reg pressures are at 175 and 130 respectively and are staying there even after sitting overnight.

Next week I will make it out to the range and see how the groups are at 35, 50 and 75 yards; might do 100 if I like how the other distances are going. I had a great grouping at 100 before the first reg issue but I'm really just going with my realistic shot distances for hunting.

You figure, even at 875fps I'm still getting 137ft/lbs at the muzzle and that's plenty for what i'm doing. If I push to 75 yards, furthest I want to shoot, its still roughly 94ft/lbs and thats with a pellet. 

Hopefully you'll get your rifle back shortly and be back at it again.

 

[7Green]

 

[7Green]

Well that was a slow pia, but I got it. I purchased a 3/4 oz Tungsten barrel weight and used a dremel with a 1/8" Tungsten Carbide tip to drill out the center to fit the valve rod diameter. Very slow process. Next step is to drill out the hammer and epoxy it inside. My goal is a 33 to 35 gram hammer.

 

[7Green]

The 3/4 oz Tungsten barrel weight itself weighs 19.17 grams after being drilled out. I drilled out a 1/2 oz barrel weight too and it weighs 12.11 grams. The hammer drilled out weighs 12.3 grams. My goal is the 33 to 35 gram range with full adjustability of the Micro dial. Using my Micrometer, I think I may have to use a combination of the 1/2 oz Tungsten weight and a brass hammer to get near there. Trial and error lol.

 

[7Green]

32.08 grams with the hammer, brass weight at 7.67 grams and 1/2oz tungsten insert. May hit 33 or more after epoxy and delrin insert is put in. 

I used one of the spare hammers I had. The wrong one with the insert on the hammer vs. the C1.

 

[7Green]

Looking like it will end up close to 32.5 grams with no washers and using my 7.67 gram hammer weight. Epoxy is set and I will check it in the morning when it cures. I used pro-bed 2000, gun bedding.

 

[7Green]

 

[7Green]

If I were to order a hammer from FX that doesn't have the delrin insert, one could make one around 33.5 to 34 grains. You could hit close to 35 grains if the washers are used too. 

Just so everyone knows, I drilled out the hammer first with a 1/4" drill bit until there was approx. 2mm left of material. I then used a 3/8" drill bit until I got to where I stopped with the 1/4" bit, leaving around 2mm of material left still. My micrometer was used to measure this. 

The original void in the hammer was approx. 20mm deep. The length of material on the wide section was around 35.5mm long. My goal was around 17mm of depth left in the hammer since the oem hammer weight and 1 of the washers would put you near max on the micro dial. I ended up 1mm off my target depth. See drawing below.

 

[7Green]

I also think if I could get a hole in one of the original Tungsten weights I ordered it would be better. Tighter fit and shorter length, saving more of the original hammer material. This would also save some additional weight. Below is a photo for the comparison. Top is 11.27mm long and bottom is 14.88mm long. 9.49mm wide is the top and 8.86mm wide is the bottom. Both weigh approx. 1/2 oz.



I may have to buy some spare hammers from FX in the future. If I do, it would be the one with out the delrin insert.

 

[ram2jeep]

That's some fine work you have done there! Can't wait to see the results of all the hard work you put in...

 

[7Green]

Yep. I just have to figure out when I want to take her apart again lol.

On a side note, with the original factory hammer, hammer weight, and 2 washers installed; the max micro adjustment range was around 4.6 on the dial. With one washer removed, it would be near the 5 mark on the dial. This was how I came up with my target depth range. 

Personally I don't think there should be numbers 1-5 on the gun because depending on what internals are installed, it will dictate how much adjustment you have on the micro dial. All of it is dictated by full compression of the hammer spring. 

My thought is to get full adjustability of the dial for a better range of velocity adjustments. Plus, I would prefer to get the max velocity out of the gun while on the max Macro and Micro settings. A true 1-16 Macro and 1-5 Micro would be perfect. 

Lastly, I don't know at what weight the hammer assembly achieves its max energy. 29.12 grams opened up the valve at 165 bar with velocities in the 930 fps range (81 JSB's) and near the 860 fps range (93 NSA'S). My Huma reg is rated at 200 bar. If I could open it at say 185 to 190 bar, will I see a velocity increase? Only testing will answer the question.

Honestly, I would be thrilled if I achieve near full Micro adjustment and 870 fps with the NSA's. 

The last and final step would modifying the porting of the gun with an external plenum and modified valve assembly, to allow a larger volume of air to flow when the valve opens. 

 

[mtndragon]

That's some fine work you have done there! Can't wait to see the results of all the hard work you put in...

I concur-this is excellent work and documentation. Thank you for sharing and bringing us along on this experiment. I am eager to see what you get in terms of power and accuracy.

 

[7Green]

No problem.

I started this project and idea because I couldn't find any legitimate info on the gun or anything about what others were achieving with the .357 version. No matter how hard I searched, all I saw was info about accuracy and what the gun could supposedly do. 

When I first recieved the gun, I was not able to even get close to the max rated energy levels of the gun. Now I just want to see what it is really capable of. 

 

[7Green]

Here I go again.

 

[7Green]

So adjustability peak at about 4.7 on the Micro dial now. That 1mm I was off from my target 17mm depth appears to be nearly exactly what is needed for full range of adjustability. I hit 16.03 mm. So close lol.