FX FX Maverick 30

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Mrclean4ya

Mrclean4ya

Member
May 19, 2025
22
15
Chesterfield, VA, United States
I am new to the Maverick /PCP in general. I have 700 and currently running 44.75 gr JSB. Apparently, the Maverick I bought has a FX slug kit installed by the original owner. I can shoot 44.75 at 75 yards with a group at 8.6mm. I tried to put some 45gr Zan HP slugs in for giggles and the 1st one didn't seem to want to go in almost like it was stuck. I kind of tapped or jiggled it and it went in. I shot and it didn't seem to hit the target. (Later found out it shot high) Next slug went smooth hit target with minimal poi shift. Next few slugs had the same issue with not wanting to feed. It was like they were slightly larger or something. I have seen a video where they talk about the pin probe getting stuck on the mag so maybe this is the issue. Somone else suggested could be rough edges. Was hoping to get some input or somethings to check. I'd like to shoot a heavier slug around 54-60ish with as much fps as possible for yotes but still remain accurate chrono should be here today to be able to check the tune properly but doesn't do anything if the slugs feel this hard to load. Where should I start pellet sizer, tear it down, check mag etc.
 
Did you have any problems with feeding when shooting pellets? Of not than i don't think you have a problem with your probe. Maybe you can take a picture of the breech and probe. Might be something off.

To be honest though. I think you really are stretching the capabilities of the Maverick when trying to shoot 55gr slugs with it.
 
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The difference between FX liners, standard vs heavy should only be twist rates. No change in liner wall thickness or breech size. Should not have any effect on if slug of right caliber feeds. 30 caliber slugs can vary though, .300-.303 depending on manufacture for specific barrels. FX liners are .300 so anything bigger would be tough. Are you single feeding? With pin probe that can be an issue. Pin probe has very small surface area pushing slug, so if it’s not perfectly inline, it will push it to one side or the other and grab on side of breech of liner. Feeding from magazine usually solves the issue or pushing slug in to breech by hand.

If your pellets are feeding and shooting fine, then your pin probe isn’t bent and your liner is fine. Most likely culprit is how the slug is being fed or slug diameter.
 
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CoyoteGod said:
The difference between FX liners, standard vs heavy should only be twist rates. No change in line wall thickness or breech size. Should not have any effect on if slug of right caliber feeds. 30 caliber slugs can vary though, .301-.303 depending on manufacture for specific barrels. FX liners are .300 so anything bigger would be tough. Are you single feeding? With pin probe that can be an issue. Pin probe has very small surface area pushing slug, so if it’s not perfectly inline, it will push it to one side or the other and grab on side of breech of liner. Feeding from magazine usually solves the issue or pushing slug in to breech by hand.

If your pellets are feeding and shooting fine, then your pin probe isn’t bent and your liner is fine. Most likely culprit is how the slug is being fed or slug diameter.
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Tried them out of a brand new FX mag. Have an older mag I can try also. I saw a youtube video this morning where they said the pin probe could be pushing the slug in before the probe was through the mag and thus the mag was auto rotating before the probe was all the way in so this is something I need to check. It was at or around the 10 minute mark not sure if this is possible or not.

 
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In my experience with fx maverick .30 sniper and slugs is that the cheek rest is keeping the magazine from fully seating to it's home position. Take the cheek rest off of the gun and start shooting that way. If that solves the slug jamming problem, then it's a crappy cheek rest that needs to have a lot of material sanded off of it so that it NEVER touches the magazine in any way ever again.

stovepipe
 
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So the factory mag is smaller definitely. The pellets go in smooth as silk. The slugs are more tapered than the diablo. I'm wondering if the mag is closing trying reload the next pellet. Before the probe is all the way in.

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So watched a few of Ernests videos and if I cock the rifle back I cant put the mag in. I have to hold the cocking handle back to get enough clearance. I'm wondering if the probe is out too far and pushes the pellet of of the mag before the meat of the probe can clear the mag. Basically the hang I'm feeling is the mag not the breech. Will post a picture or so.
 
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I've noticed a previous owner has drawn a sharpie mark but I don't know why or what for. Like I said pellets are smooth slugs not so much. My calipers dont read tight enough only to the hundredth. I rekon tomorrow I can try to just load 1 pellet into the mag and see if that runs smooth or place a single pellet in by hand and see if it's smooth that way.

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Dump the pin probe. It sounds like the previous owner wanted to shoot slugs and didn’t do a complete job of putting all the stuff together correctly.
I have 4 FX slug guns and there is not a pin probe in any of them. The velocity gain is minimal and common sense should tell you that the larger surface area of the stock probe is going to be more stable and provide a better seating than some tiny pin that is prone to bending and not being perfectly aligned with the path of the projectile into the breech.
I rant about FX and the attendant snake oil that has soured many a shooter on FX. Somewhere the lie that all that crap is necessary for an FX to shoot well got started and has been fertilized with the frustration of people doing DIY upgrades that they do not wholly understand and therefore do not successfully install.
If you doubt me just enter FX tungsten hammer and read all the posts about how “it aint working like I thought it should.”
 
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I think the previous owner tried to modify this rifle to shoot slugs and got frustrated with it and sold it. FX rifles come from the factory set up to shoot pellets and they do that well. Slugs are a different animal requiring boosting power to shoot slugs at a higher velocity (not always), different barrel twists rate, probes, and other power boosting mods. You will likely have to experiment with slugs of various weights, diameters, and manufacturers to find the right one. In essence, it’s a different gun. Why? Some think they are more accurate, better killers or? Pellets shoot well up to 100 yards. I tried them in a number of my rifles and was never really satisfied with any of them except my HM1000x in .177 caliber that I had custom built for that purpose. I suggest returning your rifle back to its original configuration and enjoy shooting it with pellets. Or, if you enjoy tinkering, have fun.
 
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Hi Mrclean4ya. The pin probe you are using has a freakishly long section of bevel between the "pin" diameter of it and the "full .30" diameter of it. That could explain what you are saying about the magazine trying to advance while the slug is being pushed into the breech. So your pin probe looks problematic to me. I would not use a pin probe like that. Although pin probes can be more efficient with air and give you a bit more power, the use of them is more complicated than I think you are ready to mess with. They need to be matched to the slug you are using in terms of the shape of the base of the slug. Like others have recommended -- I also recommend that you just switch to using the stock pellet probe, since it will work for slugs and pellets. Leave the use of pin probes for later when you better understand the maverick.

Once you switch to a pellet probe, your slugs might still have snagging problems going into the breech. This can be caused by a magazine that has a loose screw. Look at the back of the mag at the hex nut and make sure the machine screw is threaded all the way into the nut and it should be flush with the nut.
Another COMMON problem is like I said in my previous post -- your cheek rest could easily be blocking the magazines from seating fully into their home position. From the picture I see, it looks like someone did a little sanding on the cheek rest to try to eliminate the mis-alignment problem with magazines. There is a good chance that they really did not remove enough materal from the cheek rest to guarantee that it will never touch a magazine again -- ever.

Good luck.

stovepipe
 
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I have to work on a heat pump this afternoon. So I may not get around to it today, but tomorrow I'm open. We're gonna pull some stuff apart and see what we can break. I am a pretty mechanical person.
Once I take everything apart, I think I'll have a better understanding of what's going on. I will keep everybody updated on my findings
 
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CoyoteGod said:
The difference between FX liners, standard vs heavy should only be twist rates. No change in line wall thickness or breech size. Should not have any effect on if slug of right caliber feeds. 30 caliber slugs can vary though, .301-.303 depending on manufacture for specific barrels. FX liners are .300 so anything bigger would be tough. Are you single feeding? With pin probe that can be an issue. Pin probe has very small surface area pushing slug, so if it’s not perfectly inline, it will push it to one side or the other and grab on side of breech of liner. Feeding from magazine usually solves the issue or pushing slug in to breech by hand.

If your pellets are feeding and shooting fine, then your pin probe isn’t bent and your liner is fine. Most likely culprit is how the slug is being fed or slug diameter.
Click to expand...
Thanks for the info. I didn’t realize the heavy slug barrels were only different in twist rate.
 
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