"SIZE" does matter

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LIVIT

Member
Jan 5, 2017
131
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NC
 I just recently got setup to test a theory I had previously mentioned and didn't get what I would call positive responses too. This will be an on going test over the next few weeks.
Rifle: XS46U ( my FT rifle) Scope: UTG/Leapers 3-12x46 w/80 mm sidewheel Pellets: JSB RS 7.33g, H&N FTT 8.64g and CP magnums 10.5g. I will be trying more pellets soon to confirm my findings. Chronograph: Caldwell G2, .177 Pelletgage, Caldwell Bi-pod and Caldwell field pod, Splatter burst 2" targets.

I weighed all my pellets using a .10g mean IE: 7.33grain pellets 7.23g - 7.43g kept as acceptable. I used a pelletgage and separated pellets into groups IE: 4.48mm, 4.49mm, 4.50mm etc... I had bought H&N FTT in tins marked and advertised at 4.51mm, 4.50mm etc. DONT count on that being whats in tin. Glad I have a pelletgage.

I do want to mention that I just started shooting the XS46 this past weekend, but that said, I am getting surprising good accuracy. This rifle was used but like new, never had a scope on it previously and a friend on AGN and member of the THAGC hooked me up. He is going to possibly wish he had not sold it :) I also just finished moving so pics will be posted once I find my digicam.

First Test is at 25yds.
JSB RS 7.33g 4.50mm group smaller than a dime. 4.51mm all 5 touching or in same holes, same with 4.52 and 4.53mm. 4.54mm group opened up a lot
H&N FTT 8.64g 4.51,4.52 and 4.53mm, same results and these and the JSB's had exact same POI.
CP mags 10.5g 4.51, 4.52 and 5.53mm same results, just a slight different POI.
I then tried some 4.48mm and 4.49mm of all three and the groups opened up and I had several flyers.
My theory is, it is not so much the brand as it is the size and shape. My rifle very obviously likes pellets in the 4.51mm - 4.53mm size. If I had just pulled pellets straight from tin and had grabbed some smaller than 4.51mm and larger than 4.53mm, I would of determined that my rifle does not like Brand X in style X. I believe it is more making sure of weight and head sizes and pellets with same type of shape, all my test pellets are domed.

This weekend, weather permitting I am going to chronograph and then move target out to 35yds, 45yds and 55yds. I am also going to be doing same test using a .22 soon as I get my .22 pelletgage. I should have pics or vids of this weekends results.

 
I got to do some testing today with my new Caldwell G5, I like it but the included tripod is not much.
H&N FTT 8.64g 4.51 and 4.52mm averaged 870fps the 4.54mm averaged 850fps and poi at 25yds dropped 1/8th inch and the group opened up some.
JSB RS 7.33g 4.51 and 4.52mm averaged 932fps the 4.54mm averaged 911fps and poi at 25yds dropped around 3/16th inch and the group opened a lot.
 
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Got to do a bit more testing yesterday between unpacking (just moved) I am out of the JSB RS 7.33g 4.52mm so I was shooting the 4.49 and 4.50mm at 35 yds. groups were quarter size. Then I shot the H&N FTT 8.64g 4.52mm groups smaller than a dime, but most interesting thing was that the poi of the 8.64g 870fps pellet was almost 1/2" higher than the 7.33g 932fps pellet !! 
I did not chronograph the 4.49/4.50mm in my original testing. I will do chrono test wed/thurs when I am off again. I think I am going to find that the 4.49/4.50mm pellets are going to show a good bit lower FPS than the 4.51 - 4.53mm due to how the pellets are fitting the bore and allowing air to bypass. Any thoughts ?
 
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More testing the past few days. 40 and 45 yd results. H&N FTT 8.64g, the 4.52 and 4.53mm head size are giving me 10 shot groups smaller than a dime. 4.51mm have opened up to a group the size of a nickel. Results are the same with the Crosman 10.5g, but the gun is definitely more hold sensitive with the heavier pellets. I did chrono the JSB RS 7.33g 4.49mm and my results showed my suspicions to be correct, they averaged 903fps compared to the 4.52mm that shoot at 932fps. 

I have got some more different pellets on the way to compare. I am also getting a .22 pelletgage and will repeat same tests with my .22 Gamo. I don't know yet if its just that I have a gun that is not brand picky, its just head size picky or if this is going to hold true for any air rifle/pistol. I plan on testing my theory on several more air rifles as I buy them.
 
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May I suggest trying the Crosman pointed 7.4gr hunting pellets in the tins of 250 from Wal Mart and the Crosman Premier 7.9gr domed and Premier Hollow Point 7.9gr. They worked well when sorted in my spring guns as well as others have mentioned to me with great results as well when sorted/sized. Don't waste your time with the Crosman Premier Pointed 7.9gr in the 500ct tins. Those were shot and scattered all over the place through several springers.

Others to consider China made super cheap Beeman black coated Hollow points (Silver bear copies).
Gamo Match wadcutter. Don't knock them till you try them!

I pretty much tried just about every pellet imaginable out there.

AJ
 
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AJ, you must of read my mind. I have the cpl 7.9gr domed and the JSB 8.4gr domed on order and if it dont start raining again today I am going to shoot some of the crosman hp 7.9gr.. and shoot the H&N FTT at 55yds to see if they keep grouping as well at the longest range I will be shooting in FT competition. I was thinking about testing some other shapes once I got a good mix of domed pellets tested. I wish that crosman made those 7.9gr domed in something other than a 1250ct. If I find that the CPL and JSB domed pellets in the 4.52/4.53mm group as well the others I have tried, then I think I have proved that my theory, at least for my springer is correct.
 
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Got the Crosman premier lights 7.9gr, unfortunately most the box is 4.54mm. But did get some 4.53 & 4.52mm. They chrono at 903fps average and shoot around a dime size group at 35 yds. But, at 15yds there grouping around 3/8" lower than the H&N FTT 8.64gr that chrono at 870fps. At 35yds there grouping almost 1/2" lower than the H&N FTT. 8.64gr I am use to alot of PB shooting and trajectories etc. If you have projectiles with similar bc's and one has a higher fps then it logically hits a bit higher at shorter range (150yds with a pb is short range to me) I would think that it would apply 10-35yds with a air rifle. I had similar results with the JSB 7.33gr hitting lower than the H&N 8.64gr. I am a bit confused, all the groups are similar in size, yet why would lighter pellets group lower ??? I did check some pellet trajectory calculators and all the other pellets are grouping exactly where they should be in elevation. It seems any pellet I am shooting that exceeds 900fps is hitting lower ? Some help please !

I am going to test the JSB 8.44gr domed next. They should put me in the 885FPS area.
 
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"LIVIT"I am a bit confused, all the groups are similar in size, yet why would lighter pellets group lower ??? I did check some pellet trajectory calculators and all the other pellets are grouping exactly where they should be in elevation. It seems any pellet I am shooting that exceeds 900fps is hitting lower ? Some help please !

I am going to test the JSB 8.44gr domed next. They should put me in the 885FPS area.
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This is a good thread. You have been working on something for a month that has been tickeling the back of my mind for quite a while and I've only just come to the party.

The gun vibrates during the shot cycle. Those vibrations travel all along the rifle and "bounce" off the ends or are absorbed at the points where you contact it with your clothing, the rest, or you body. If the rest is hard they are not absorbed but reflected back into the vibrating mass of the rifle. These movements are not really predictable but they are repeatable when they happen to be the right frequency. They are not repeatable when they are not of the right frequency.

A tight group indicates that the vibrations at the muzzle are at a node. A node is a place where the "system" is not in motion. You can see this effect when you watch ripples on water. If you put a hard surface into the water the ripples will even bounce off of it and change direction. So again, a tight group indicates that the vibrations at the muzzle are at a node. A large group indicates that the vibrations at the muzzle are at an antinode, a place where the movement caused by the vibration is largest.

Now then anything that changes the system. Pellet weight, diameter, trigger finger placement, how you cheek the weapon, the point at which you rest the weapon, ANYTHING different that happens between one shot and the next changes these vibrations. If the system is not resonant (the node is at the barrel) then you get a change which decreases accuracy. If the thing you do makes the system more resonant then you get a change which increases the accuracy.

These changes can cause POI changes which are counter intuitive. That is what you are seeing.

Keep up the good work.
 
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Hi Mike and tks buddy. This had me scratching my head rather vigorously. I have been very careful to rest my rifle in the Caldwell fieldpod cradles the same every shot. The "Harmonics" never came to my mind, but it now makes complete sense. If I was to change how I rested the rifle in the cradles then possibly all the poi's might change and the 7gr pellets could actually end up hitting higher as they should of been, but my groups could open up too ! Again tks my friend.

I have the JSB 8.4 gr on order and they will be the last of the .177 domed I will be testing. Weather permitting I will be shooting out too 55yds this weekend and hope to have vid or at least some pics of groups. Another test I am going to be doing is something my bud "Campfussel" mentioned, the difference in a lubed and non lubed once you find the "perfect for your gun pellet" I am also planning on testing some other type of .177 then do the same for the .22
 
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You need to run the larger Crosman pellets through a sizing die and you won't believe how accurate they will become when you shoot sized Crosmans. If you can find an old Beeman pell sizer with .1785 die it would be perfect which is 4.5339 and is the magic die size for most of my HW springers which enable accurate reliable shots past 60+ yards in 177. I would think modifying a pellet pen could work if you can think of a way to give it a choke which would consistently shave them as they come out.
AJ
 
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