Large Chrono'd Foot Pounds Variations??

[davethedood 1]

Been having trouble getting my groups to close up.

Recently had the gun (secondhand AA Prosport springer) relubed by a local gunsmith and it seems to shoot smoother than before but doesn't seem very consistent.

Just chrono'd using JSB Exacts with results ranging from 737 to 763 foot pounds over less than 10 shots.

I've never done this before but that seems like quite a large variation and thought maybe my spring is tired- any ideas?, is it time for a full tune up with a new spring etc?

Any advice/recommendations welcome

[barrywhite 282]

if your gun is shooting 737 to 763 foot pounds you could try shooting some big game .

[andyfr1968 772]

That is a pretty big variation. What was it like before the service?

 

Bear in mind though that it will take some time before it fully settles down after major surgery. Give it a couple of hundred shots minimum then check again.

[davethedood 1]

Ha ha yes, feet per second not foot pounds!

 

Don't know what it was like before the service as I only just got my own chronograph. But it was a bit twangy before, nice and smooth after the service, but less accurate

 

I have already put about 350 pellets through it, so it hasn't settled down yet.

[davethedood 1]

Or it has had time to settle down but is still inconsistent...

[andyfr1968 772]

After that many shots it should be well and truly settled by now. If the accuracy's gone to pot then it probably rules out a dodgy chrono assuming that it shot well with the same pellets before, so the next likely culprit is either the breach or piston seal.

[davyt63 1,840]

just out of interest,what chronograph are you using?

[Skot Ruthless Teale 1,701]

I use a combro but dont really trust it. want an f1 or something similar but cant be bothered paying a load more dosh for it lol

[ghillies 209]

hmm on a springer? has it settled down after the tune because that is really bad. i'd try some other pellets if its had a few through already and if it didnt clean up i'd be wanting monies back or something.

[davethedood 1]

Daveyt63 I'm using the combo cb 625 attached with electrical tape.

 

andyfr1968, just been through 8 pellet types as I was doing a test to see which was best in my barrel, sent some vfg cleaning pellets down the barrel and releaded between each pellet type, groups ranged from 12mm to 24mm at 27 yds which didn't seem very good to me. My groups were better before.

[Skot Ruthless Teale 1,701]

my 95k is 12 fps spread with jsb exact and 30+ fps spread with daystate Li

[davethedood 1]

Thanks Skot, think I'll try chrono with the other 8 pellet types and see what happens..

[Skot Ruthless Teale 1,701]

as somebody once told me, dont get wound up too much by the numbers..

 

i got really frustrated with my old rifle and got rid of it, but there was actually nothing wrong with it.. it was still giving 5p groups at 35 yards when i did my bit but i got too wouynd up by inconsistent chrono results!!

 

so thats my advice, dont worry TOO MUCH about it.

if it still shoots fine ...

 

good luck mate, SKoT