FX Impact M3 Upgrade Issues

[Squirrelmageddon]

I have an M3 500mm .22 pellet setup for pest control and < 100 yard target shooting. I recently added a second M3 .25 700mm slug setup for > 100 target shooting. It shot great out of the box with NSA 26.8g @ 960 FPS. I wanted more out of my investments and ordered 2x slug power kits and a 700mm barrel tensioner kit. Now here's what I ran into after a bunch of testing and headache.

1) The pin probe - On the 700mm after a dozen or so shots I had flyers all over the place. I couldn't consistently get my shots to group at 20 yards. I thought my dam scope was broken. I added the CB shroud and a new Impulse Air 1350 moderator so I pulled the mod and put the stock one back on with no change in accuracy, So I pulled the CF barrel tensioner off and still had the same results. Later that afternoon, after lots of swearing, I pulled the moderator apart to check for pellet clippings. Sure enough there was a huge load of lead dust and slivers inside the IA and stock moderators. So I started to track down alignment issues. Why the hell is the moderator not lined up? I know my pin probe was seating the slug a sliver past the S port so it couldn't be the probe. I checked my probe alignment as I've heard of the top screw coming lose and the probe going cockeyed. It was fine. I pulled the barrel and low and behold, it was filled with lead particles. Turns out shallow dished slugs go all cockeyed with the small pin. Installing the stock pellet probe fixed the problem. The 10 FPS gain from the pin probe is not worth the potential problems IMO.

So I started putting lead downrange with my 500mm setup and new pin probe. I paid attention to feel when the probe was pushing the slugs in the breach. I could actually feel maybe 1 out of a dozen stick while feeding. I'm pretty sure the slug was not straight and caught the transfer port edge. I pulled the barrel after shooting a slug that got hung up and there was lead particles in the barrel which is exactly what happened on the 700mm gun.

Pin probe = no bueno.

2) CF Barrel Tensioner - The whole design had my eyebrow raised when I first installed it. The system is so dependent on the ends of the tubing to be cut perfectly squared. I've read a post on another forum with an Impact owner that had a funky cut tube where it would tweak his barrel. Sure enough my tube does the same thing. If you accidentally loosen the end locking nut by unscrewing your moderator and the tube spins, your shot placement shifts. I actually took a sharpie and marked my tube. I spun it in 90 degree increments and the groups shift matching the tube rotation. The dam tube is not squared up. What a bummer.

 

[Airgunmann]

It wouldn't take long to true it up in a lathe but still after paying for it shount have to do that

 

[jps2486]

Upgrades? The M3 is supposed to be the end-all of air rifles.

 

[Airgunmann]

I don't care how much is spent on a rifle someone will find something they want to change or something to upgrade

 

[Vetmx]

The only mistake you made was taking two supposedly great shooting guns then screwing them up with trinkets and do-dads. Never poke a great shooting Impact with a stick. If it’s shooting great, treat it better than your wife or girlfriend. And to be PC, possibly your boyfriend or life partner. Now we wait to see if you can get that 960fps previously great shooting gun back to what it was. I wish you luck. Sometimes it’s hard to find where your gun once was.

 

[Dirtnap]

This is the best response I have heard in a long time from @Vetmx. Spot on.

DN

 

[Squirrelmageddon]

The only mistake you made was taking two supposedly great shooting guns then screwing them up with trinkets and do-dads. Never poke a great shooting Impact with a stick. If it’s shooting great, treat it better than your wife or girlfriend. And to be PC, possibly your boyfriend or life partner. Now we wait to see if you can get that 960fps previously great shooting gun back to what it was. I wish you luck. Sometimes it’s hard to find where your gun once was.

I concurr. I have the pellet probe back in along with the stock shrouds and I'm back to nice groups again, at least on the 500mm. I'm still tuning the 700mm for slugs, however, that one is pretty close at 960 FPS. Lesson learned for sure.

 

[7Green]

The only mistake you made was taking two supposedly great shooting guns then screwing them up with trinkets and do-dads. Never poke a great shooting Impact with a stick. If it’s shooting great, treat it better than your wife or girlfriend. And to be PC, possibly your boyfriend or life partner. Now we wait to see if you can get that 960fps previously great shooting gun back to what it was. I wish you luck. Sometimes it’s hard to find where your gun once was.

Meh. These guns aren't rocket science, nor difficult to work on. Besides, at some point one of the bazillion orings will need to be replaced anyhow. The more you mess with them, the more you learn and the quicker and easier it becomes. I have faith the op will figure it out.

 

[Squirrelmageddon]

Meh. These guns aren't rocket science, nor difficult to work on. Besides, at some point one of the bazillion orings will need to be replaced anyhow. The more you mess with them, the more you learn and the quicker and easier it becomes. I have faith the op will figure it out.

Ya I figured it out. It's definitely a pin probe problem. I loaded a full 25 round magazine one at a time, paying attention to how smooth they fed. After each slug, I removed the mag, and pushed the slug back out of the breach with a cleaning rod. Some of the pellets were damaged. I could actually feel them snag up while feeding. 3 or 4 out of those 25 most likely went in cockeyed and got caught up on the sharp transfer port edge. I pulled the barrel and sure enough I had lead dust and a few particles in the barrel near the transfer port. That debris in the barrel is what was built up in my moderators because it was getting shot down the barrel.

I tested some shallow dish slugs like the NSA and H&N and those have the most issues with the pin probe. Deeper dished slugs from Rifle feed more consistently because they have a deep pointy pocket and it seems like the slug centers up on the pin because of that. Anyways, the large flat faced pellet probe keeps them lined up nice with only a minimal 10 FPS loss.

Now this had my mind whirling. Why does a cheaper gun like my Kral Empire feed perfectly with a similar pin probe? I used the NSA .249 26.8gr slugs in the Kral and the FX to see what the difference was. On the Kral, as the slug enters the breach, it immediately tightens up and feeds straight. When the slug is past the transfer port it's pretty snug. On the FX, the breach is opened up a bit. If you push a slug into the breach but not past the transfer port and turn the gun barrel up, the dam slug falls right out. I can feed the slug all the way past the transfer port, shake the gun, and the slug starts backing out of the barrel. It's that loose fitting. WTH! No wonder the slugs go all cockeyed here and there.

 

[Vetmx]

I concurr. I have the pellet probe back in along with the stock shrouds and I'm back to nice groups again, at least on the 500mm. I'm still tuning the 700mm for slugs, however, that one is pretty close at 960 FPS. Lesson learned for sure.

Excellent. When you find the right tune with the 700mm, just enjoy shooting. There is still plenty to keep you occupied. It’s not as fun as spending money on stuff but way more important. Learn how many shots you can go before you clean. Learn if it’s just a couple dry patches or a chemical bath. Anywhere from 930 to 970fps is all you’ll ever need to blast stuff. We’re not hunting lions with these peashooters.

 

[Chukar60]

Ya I figured it out. It's definitely a pin probe problem. I loaded a full 25 round magazine one at a time, paying attention to how smooth they fed. After each slug, I removed the mag, and pushed the slug back out of the breach with a cleaning rod. Some of the pellets were damaged. I could actually feel them snag up while feeding. 3 or 4 out of those 25 most likely went in cockeyed and got caught up on the sharp transfer port edge. I pulled the barrel and sure enough I had lead dust and a few particles in the barrel near the transfer port. That debris in the barrel is what was built up in my moderators because it was getting shot down the barrel.

I tested some shallow dish slugs like the NSA and H&N and those have the most issues with the pin probe. Deeper dished slugs from Rifle feed more consistently because they have a deep pointy pocket and it seems like the slug centers up on the pin because of that. Anyways, the large flat faced pellet probe keeps them lined up nice with only a minimal 10 FPS loss.

Now this had my mind whirling. Why does a cheaper gun like my Kral Empire feed perfectly with a similar pin probe? I used the NSA .249 26.8gr slugs in the Kral and the FX to see what the difference was. On the Kral, as the slug enters the breach, it immediately tightens up and feeds straight. When the slug is past the transfer port it's pretty snug. On the FX, the breach is opened up a bit. If you push a slug into the breach but not past the transfer port and turn the gun barrel up, the dam slug falls right out. I can feed the slug all the way past the transfer port, shake the gun, and the slug starts backing out of the barrel. It's that loose fitting. WTH! No wonder the slugs go all cockeyed here and there.

why does the Kral work So well with a similar pin probe? Because that is the way it was designed. If FX thought the pin probe was such a great idea and they were promoting accuracy and power it would already be in the gun. It would be a cheap feature to make standard. Lo and behold it ain’t there.
Same goes for how the slugs chamber. Once you have an FX gun tuned to shoot slugs it will shoot with any other slug gun.
The rabbit hole people complain about does not exist until we dig it with our own minds.
We have 5 FX guns in house and not one of them is sporting anything aftermarket except the moderator and scope. They shoot just fine. My first FX gun I was YouTub ‘d and spent an inordinate amount of time and money trying to make it better. Lesson learned. They are great guns without all the garland, chrome and lipstick.