Reply To: "4.52mm" 8.4 grain Exacts sorted "holes in a plate" vs digital caliper.

Forums Pellets, Projectiles, Slugs, & Ammo "4.52mm" 8.4 grain Exacts sorted "holes in a plate" vs digital caliper. Reply To: "4.52mm" 8.4 grain Exacts sorted "holes in a plate" vs digital caliper.



I never realized how precise 1/100 th of a mm was till I tried to machine my own pellet sizer (.01mm= 0.00039in)

To make a usable pellet head sizer I first had to make a "D reamer" that with a 4mm sizing ring……….

Then I drilled a 4mm hole through a piece of O1 tool steel and used the reamer to ream out the drilled hole to rough dimensions……….

To achieve the final pellet head size I had to lap the sizing ring till a sized pellet was the correct dimension as determined by the fit in the barrel leade.

The 4.48mm sizer was for my .177 HW95  and the 4.52mm sizer was for my .177 Beeman R9. I later found that lapping the 4.48mm sizer to produce a 4.50mm pellet head produced a pellet that was accurate in both the HW95 & R9 without the excessive "sore loading finger pressure" of pushing an unsized die lot marked and dated boxed 7.9 grain die "B" Crosman Premier which have pellet heads ranging from 4.53mm to 4.55mm.

Unsized CPLs from my stash of die "B"s dated Feb 3 2014……….

Anywhoo….after making a few pellet head sizers I give some slack to pellet head sizes straight from the tin! I've even come to the conclusion that as long as the smallest pellet head in the tin is large enough to be "sized slightly" when loading into the leade, all pellets that follow will be a consistent fit in the bore regardless of the size variation in the tin. The problem comes when some tins of pellets are labeled 4.52mm but the majority are smaller than the leade so they aren't "sized slightly" when pushed into the leade.

A perfect example of this is trying to use supposedly 4.52mm JSB Exacts in my looser leade .177 Beeman R9 because very few of the Exacts had 4.52mm pellet heads. LOL…..trying to size a tin of the supposedly 4.52mm Exacts using a 4.50mm die simply gave most pellets dropping past the sizing ring without sizing at all. As mentioned previously, I recently bought 4 tins of 8.4 grain .177 Air Arms Domes marked 4.52mm and all but a few were actually sized using my 4.50mm die. One tin was dented before packing and it did have a few pellets with deformed skirts………..