strange loss of accuracy

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Spash

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Jun 8, 2015
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East Flanders
I hope you guys can help me out because i'm a bit stumped by this one.
2 days ago my p12 was shooting lights out at 50 yards but yesterday i started shooting and couldn't keep groups in 2 inch...
opened everything up, didn't see anything strange, put back together and shot some groups.

Strange thing is every once in a while it will start shooting good groups again, i go check them and when i shoot the next they just scatter all over the place again :(

maybe a very thourough barrel cleaning might do the trick?
 
"Spash"I hope you guys can help me out because i'm a bit stumped by this one.
2 days ago my p12 was shooting lights out at 50 yards but yesterday i started shooting and couldn't keep groups in 2 inch...
opened everything up, didn't see anything strange, put back together and shot some groups.

Strange thing is every once in a while it will start shooting good groups again, i go check them and when i shoot the next they just scatter all over the place again :(

maybe a very thourough barrel cleaning might do the trick?
Click to expand...
Maybe the causes for loss of accuracy could be the following. 
1. Barrel cleaning 
2. Check the scope rings once. It's possible that they aren't holding the scope properly even though they may seem tight. I had this problem once and it turned out to the the scope rings. Switched to BKL rings and never looked back 
3. Try another scope. Sometimes scope dont hold zero very well. 
4. Try another tin of pellets. Sometimes a bad tin messes things up
5. Check if there is any clipping on the shroud or barrel if you are using a LDC or a moderator, pellet clipping could be the cause 
6. Check regulator. Wear and tear on the regulator can cause loss of accuracy 
 
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"FearnLoading"
"Spash"I hope you guys can help me out because i'm a bit stumped by this one.
2 days ago my p12 was shooting lights out at 50 yards but yesterday i started shooting and couldn't keep groups in 2 inch...
opened everything up, didn't see anything strange, put back together and shot some groups.

Strange thing is every once in a while it will start shooting good groups again, i go check them and when i shoot the next they just scatter all over the place again :(

maybe a very thourough barrel cleaning might do the trick?
Click to expand...
Maybe the causes for loss of accuracy could be the following. 
1. Barrel cleaning 
2. Check the scope rings once. It's possible that they aren't holding the scope properly even though they may seem tight. I had this problem once and it turned out to the the scope rings. Switched to BKL rings and never looked back 
3. Try another scope. Sometimes scope dont hold zero very well. 
4. Try another tin of pellets. Sometimes a bad tin messes things up
5. Check if there is any clipping on the shroud or barrel if you are using a LDC or a moderator, pellet clipping could be the cause 
6. Check regulator. Wear and tear on the regulator can cause loss of accuracy
Click to expand...
Thanks I'll start working from 1 and see when the problem ends :p
 
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Hi Spash:
I have a P12 and experienced a similar situation. I'm not sure how you set yours up but mine shoots the JSB 18s at an avg. of 929 fps. The gun likes to shoot hot and is very accurate but I've found it does foul as I was getting some unexpected flyers which was strange. A thorough barrel cleaning helped me and brought the gun back. While the gun is accurate probably not the smoothest barrels. Some JB paste might help as well which was suggested. Good luck and keep us posted!
mmoscarma
 
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"mmoscarma"Hi Spash:
I have a P12 and experienced a similar situation. I'm not sure how you set yours up but mine shoots the JSB 18s at an avg. of 929 fps. The gun likes to shoot hot and is very accurate but I've found it does foul as I was getting some unexpected flyers which was strange. A thorough barrel cleaning helped me and brought the gun back. While the gun is accurate probably not the smoothest barrels. Some JB paste might help as well which was suggested. Good luck and keep us posted!
mmoscarma
Click to expand...
At the moment it is shooting 18s at around 870, i'll crank it up a bit and see what happens, AFTER I give the barrel a nice cleaning :) ( I like to take care of my guns but the cleaning must be the most teadious thing to do :p )
 
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I have cleaned the barrel and the first 20 or so shots were simple fouling shots and after that the gun started to group better and better.
can't really be sure if the problem is fixed since the weather isn't co-operating and it's real windy.

something i did notice while looking through the barrel was that between the grooves it wasn't smooth at all, as if the tool to cut the grooves stutterd while moving through the barrel :/
 
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I love the spa p12. My spa is regulated (Huma reg) and shoots extremely accurate at 870 fps. When it starts to loose accuracy (groups start to open up) i just shoot 3 cleaning pellets through the barrel and accuracy is back. I recall tha my spa also shot great at 900 fps when it was not regulated.

Have the trigger adjusted really light and get good grouping even at 104 yards (JSB 5.52 18 grains). Just shot a few groups last saterday after shooting my benjamin marauder all afternoon and got a few nice groups within 3 cm's (edge to edge) and groups with the occasional "flyer" still staying within 5 cm's (2 inches).

Yes the spa p12 still brings a smile on my face every time i shoot it.


 
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i waited a while before posting here to see what people would tell you.

after i recieved my p12 quite a while ago i used a line drag and some patches, after shooting it for a few months and having to clean my barrel after about 3 air tube fills (somewhere around 200 shots give or take) i decided to remove the barrel and give it a good soaking.

after removing the barrel i tightly stuffed one end of the barrel with a patch and basically filled the barrel with hoppes 9 bore cleaner and capped the other end with another patch, but left a tail on the last patch i put in. every couple days i would push the tailed patch into the barrel further and further till both patches popped out (took about a week) and then followed it up with a hoppes 9 22cal nylon bore brush on a 17hmr cleaning rod (slightly smaller in diameter then the 22 and up rods to avoud at all costs my cleaning rods hitting the inside of the barrel) after scrubbing it for about 5 minutes i ran some dry patches through. then packed a few cleaning pellets with jb bore paste and pushed them back and forth about 30 times and removed them, dry patched and then cleaning pellets packed with bore paste for another 30 (so 6 felt cleaners 3 each time packed with bore paste with a sweeping of a dry patch in between)

also i cleaned my crown up as it had what appeared to be some severe chatter marks in it. i get almost a full tin of pellets through now before needing to clean the barrel. every 3 cleaning (about 2 tins) i give er a scrub with hoppes and the bore brush.

i found that there was a pretty severe amount of grease packed into the rifling even after running a drag line through it several times (life could probably been made easier with a bore snake but i had the drag on hand and the brush so used that)


i get 1/2" at 50 about 70% of the time but once in a while i get 1/4" and single hole groups when i get lucky but 1/2" at 50 fairly consistently isnt bad.


carefull running polishing compound (valve lapping) or bore paste, you can over polish the barrel doing so, however you can really feel when the barrel is super smooth by the reduction in resistance as the felt pellets get pushed in and out.

just some suggestion, just make sure you pull the barrel off the gun when using solvents like hoppes or clp, might be able to get away with ballistol as a lot of airgun guys use ballistol to clean fx guns and seem to have little to no problems with the o-rings

just some ideas for you. sometimes a line drag or wet patches just arent enough
 
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