Jamie
I've been following this post as well as Ajshoots post on how he sizes his .25 cal pellets.
I learned to slug the barrel with a pellet via AJshoots by pushing the pellet into the breech and then pushing it back out with a wooden rod from the other end. I measured 4.52 mm on my Thomas breech test.
I haven't done near as much as I would like yet but wanted to share what little testing Ive done.
I shoot a .177 Thomas FT rifle. I bought a pellet gauge and sorted a tin of 13.4 gr JSB Monsters which I shoot about 820 FPS for 20 FPE
The majority of my pellets were in the 4.54 head size with 4.53 and 4.55 being on the outer fringes for a .01 mm plus or minus for the 400 count tin which I thought was pretty tight tolerence.
http://pelletgage.com/products/177-pellet-gage I have a Gempro 250 which I weighed these head sorted pellet with. My weights ranged from 13.2 grs to 13.6 grs with the majority being 13.4 grs giving a .2 grain plus or minus tolerence which again I thought was pretty tight?
http://www.oldwillknottscales.com/my-weigh-gempro-250.html?gclid=CPSDiZTZ_NACFZKFswodOxwAPg I bought the 4.52mm and a 4.53 mm TBT head sizers like you recommended
I tried the 4.52 sizer first .
Here's the 5 shot group left target sized and the 5 shots right unsized
Looks like the 4.53 unsized group shot better than the 4.52 sized group? 1/4" grid paper
Weather was crappy and I was pressed for time before dark.
So the next I decided to use the 4.53 pellet sizer and was pleasantly surprised. The 4.53 sized group was considerably better than the 4.54 unsized group
Circles are 1/4" for comparison
I just haven't had time to do much more shooting and testing but this is really interesting to me and I agree there is something to it? I just ordered a pellet seater tonight and will also be testing to see if there are any benefits to that as well?
Oh, forgot to mention, those groups were at 28 yds and off bipod and rear bag rest. Most of my shooting is at 28yds and that's what I zero all my airgun scopes at.
Now again some days are better than others . I shot these two groups on a very calm day to compare my .177 Cricket Carbine to my Thomas. As you can see....the Cricket held it's own. Both groups shot straight from their perspective tins unsorted! 1/8" grid inside 1 inch square
Will let you guys know what I get with further testing when weather, work and daylight all come together to give me time to shoot ;-)
Great post BTW.
Jimmy