Slug Seating Depth - NSA Pin Probe - M3

[Spartan]

As I fall further and further down the slug rabbit hole...

22 cal M3. Tensioned slug barrel and heavy liner. Any advice on optimizing the slug seating depth using the NSA adjustable pin probe? Are there physical indicators to show when it is seated in just the right spot relative to the rifling?

Just wanted to see if there are any tips before I embark on total trial and error. Thanks for any info.

 

[iAMzehTOASTY1]

Oo! Look down the muzzle with a light and view the head ; when centered, that's where you want it seated

 

[Vetmx]

Your seating depth is limited by your mag. So in reality you don’t have adjustable seating depth. The second reality is a pin probe is not worth the aggravation for the measly FPS it gives you. Plus 5b on the reg will easily cover that.

 

[MongooseV8]

Your seating depth is limited by your mag. So in reality you don’t have adjustable seating depth. The second reality is a pin probe is not worth the aggravation for the measly FPS it gives you. Plus 5b on the reg will easily cover that.

With no other changes I have tested 9-20fps by swapping in a pin probe. To me its an easy choice, but I have only used Huma fixed pin probes. I didnt see the benefit to the adjustable versions. Like you mention you are limited in seating depth due to the mag.

OP: You will want to adjust forward as much as possible without interfering with the magazine itself. Too long and you wont be able to physically install the mag. Too short and you might run into a situation where the slug isnt far enough forward and might be partially obstructing the transfer port. At least thats what the salesman told me.

 

[Spartan]

Thanks all for the good info. I'm testing right now with just the stock pellet probe. Speed is not a concern with my rig as I can get well above 1000fps as-is with 30gn slugs and lighter, which is more than I need. My main reason for wanting to try the pin probe (which is currently just sitting on my table) is to see if I can achieve some increased accuracy/consistency with better slug seating.

Tomorrow's endeavor is getting the pin probe installed.

 

[TDK]

If you haven't adjusted the factory probe position, you might try that first to have another data point. I got at least another millimeter or so out of mine. I haven't bothered with a pin probe for all the reasons Vetmx stated. Stock probe is going to seat the deepest since it pushes on the edge of the projectile. I would be interested to see a back to back accuracy test of a maxed out (forward) stock probe vs a maxed out pin probe

 

[weevil]

Slugs are more apt to load consistently with the pellet probe because they cannot move off axis. Notably, the Panthera 6&700s all have pellet probes, in spite of having slug barrels and being marketed as slug guns.

 

[Vetmx]

Thanks all for the good info. I'm testing right now with just the stock pellet probe. Speed is not a concern with my rig as I can get well above 1000fps as-is with 30gn slugs and lighter, which is more than I need. My main reason for wanting to try the pin probe (which is currently just sitting on my table) is to see if I can achieve some increased accuracy/consistency with better slug seating.

Tomorrow's endeavor is getting the pin probe installed.

I wouldn’t waste your time. I’ve had four Impacts that never shot a pellet. Two of them only did when I sold them. There is a procedure I follow when I set up every Impact I buy when preparing for slug land. Number one is getting the stock probe to just kiss the liner before it retracts a little when the cocking lever is closed. Then I mark the probe, pull the barrel and probe, then slip the probe into the barrel to inspect things through the transfer port. I then get out the Dremel and get to work on the probe. With that all done, when I install a pin probe it’s maybe +10 fps. Not worth it for wobbly loading and less seating depth if you use anything with a cup or dish base. I don‘t care who uses them or tries to promote them, almost everyones Impact makes more power than they actually need with a properly set up stock probe with zero chance of a bent noodle failure at a bad time. You can’t get more consistent loading than what comes with the gun. It’s flat out square with the back of the pellet or slug throughout the whole loading process. What I find really interesting is there are quite a few guns out there that should have hot rod kits available for them. The one gun that in most cases doesn’t need it, guys order all that junk before they even learn the gun. Hats off to FX and the aftermarket for exploiting this and making a ton of money. Someone in their marketing department is a genius.