60 Yard Problem

[eddy]

Hello guys just brought a AA S400 in 177 and want to do a bit of long range plinking.
Went out today and zeroed in, it's hole on hole out to 50 yards and is accurate but as soon
as you go out to 60 yards it's like a shot gun pellets fly all over the place all I want to know
Is WHY? Ps Pellets being used 8.4 Exacts 177. Cheers

[silver fox]

this appears to be that age old thing to clean or not to clean, and i would suggest giving the barrel a clean, and i have found that at the longer distance you are shooting aa 4.52s fly much more stable than jsb exacts,and they are now my chosen pellet for all shooting, well worth a try.
atb alan.

[snock]

Hello guys just brought a AA S400 in 177 and want to do a bit of long range plinking.
Went out today and zeroed in, it's hole on hole out to 50 yards and is accurate but as soon
as you go out to 60 yards it's like a shot gun pellets fly all over the place all I want to know
Is WHY? Ps Pellets being used 8.4 Exacts 177. Cheers

Distances magnifies pellet/trajectory variances.

[simona]

I would suggest that what you are seeing might be due to the barrel.

The most accurate barrel I've ever used at 30 yards was hopeless at 50, this was shooting indoors in controlled conditions and with a wide range of pellets. The barrel was fitted to a Walther LG300 and at 30 yards the groups were virtually perfect, some 5 shot groups would support a .22 pellet. At 50 yards the same combination of gun, barrel and pellets would struggle to make 30 mm groups.

I now have a standard Dominator barrel fitted to this gun and it's slightly less accurate at close range but far better at 50 yards. The difference may be in the pitch of the rifling, the dominator barrel has significantly longer pitch. Is so difficult to understand but I presume at some specific relationship between spin and forward velocity the pellet becomes unstable.

[merc350]

I would suggest that what you are seeing might be due to the barrel.

The most accurate barrel I've ever used at 30 yards was hopeless at 50, this was shooting indoors in controlled conditions and with a wide range of pellets. The barrel was fitted to a Walther LG300 and at 30 yards the groups were virtually perfect, some 5 shot groups would support a .22 pellet. At 50 yards the same combination of gun, barrel and pellets would struggle to make 30 mm groups.

I now have a standard Dominator barrel fitted to this gun and it's slightly less accurate at close range but far better at 50 yards. The difference may be in the pitch of the rifling, the dominator barrel has significantly longer pitch. Is so difficult to understand but I presume at some specific relationship between spin and forward velocity the pellet becomes unstable.

This agrees with the theory i have that with a lot of guns used they are set up with barrels to shoot a certain distance. 10 target guns are designed to be accurate close in and accuracy drops of at distance. Hunting rifles the other way round.


It might be completely wrong though and would be interested in other peoples ideas

[walrus1#]

I would give the barrel a good cleaning before starting any serious testing especially as it is brand new,you need to get all the gunge out of the rifling and make sure the lands are polished clean.You would be surprised at the amount of grime that comes out of a brand new barrel.

[lurch_917]

I would give the barrel a good cleaning before starting any serious testing especially as it is brand new,you need to get all the gunge out of the rifling and make sure the lands are polished clean.You would be surprised at the amount of grime that comes out of a brand new barrel.

as above also i have a aa410 that is hitting a 3/4 inch group at 60 yards with aa feild pellets it took a bit of cleaning and about 50 shots to lead the barrel but is now spot on.

[Hawker Will]

I'm interested to read this thread. Cleaning the barrel is something I hadnt given much thought about regarding my own AAS410 Carbine. But a friend of mine has a BSA R10 mk2 that doesnt shoot particularly well. It seems to prefer JSB 4.52's over 4.51's. But on fairly quick cycling of the magazine, it tends to send the pellets high to up to 1 mil-dot @ 30yrds. I've told him to return the gun as its barely shot 1/2 a tin of pellets from new! We werent too sure if this was the regulator warming up due to fairly rapid fire.

I shall follow this thread with great interest!

Regard. Will

[walrus1#]

I'm interested to read this thread. Cleaning the barrel is something I hadnt given much thought about regarding my own AAS410 Carbine. But a friend of mine has a BSA R10 mk2 that doesnt shoot particularly well. It seems to prefer JSB 4.52's over 4.51's. But on fairly quick cycling of the magazine, it tends to send the pellets high to up to 1 mil-dot @ 30yrds. I've told him to return the gun as its barely shot 1/2 a tin of pellets from new! We werent too sure if this was the regulator warming up due to fairly rapid fire.

I shall follow this thread with great interest!

Regard. Will

shouldn't be the regulator heating up as compressed air cools as it is released,and expanding.Heat is caused by the compression of air,hence the tendency of spring piston guns to diesel,a phenomonon which the PCP can not do.
I would suspect that the pellets are being shaved by the magazine when it is cycled very fast and this is what is causing the pellet to go high,any deformation of the head of the pellets is what causes inaccuracy.Whereas skirt damage is mostly overcome by the blast of air reshaping the skirt and driving it into the rifling.A nick in the same position each time on a pellets head can produce the effect you are experiencing.
Graham.

[Hawker Will]

Hi Graham,

Thank you for your advice! I just took the fact that the buddy bottle got warm when filling from a divers bottle that as the air passed into the regulator every time the bolt was cocked. I'm a Marine Engineer by trade and havnt quite got my head round regulated pcp's yet, so thought I would pose the question.

Thanks again. Will

[custommy]

Don't worry about the buddy bottle getting hot when refilling from a divers bottle. This is perfectly normall and it will happen to everyones guns when being refillyed. I have heard exactly the same thing about the magazines causing indexing problems and damaging the pellet slightly. Can you manually load the gun without a mag or maybe a single shot adaptor? This would then prove if it is the magazine. I know the mk1 r10 had problems with the mags and the mk2's were revised

[Hawker Will]

Cheers Custommy,

As I mentioned, its a friends gun but I will pass on your advice. If the truth be known, he was trying to sell the gun as he didnt have use for it anymore and I was seriously interested in buying it and selling my S410 .22 Carbine. But when I took it to the rifle range and sat it on a stand it's grouping wasnt very good at all. I was selective with the JSB's I took from the tin. It did prefer the 4.52's against the 4.51's he had been using! But they group would climb. Never did it venture left to right really, only high and low.... It was consistant through the chrono at 10.8 to 10.9lbft so we figured the regulator was doing its job! But then we started to question the scope. But this was a Hawke 4-16 x 50 Eclipse IR SF which was as new as the gun itself!

Will

[riflehunter583]

i would say its one of two things.

the pellet might be starting to loose its power and spin and then starting to tumble.
or
barrel needs a pull through/clean.

i shoot mine from 30 yards to say 120/130140.

when i have shot more than 130 shots my barrel is very dirty and accuracy is poor going past say 70 yards still good close up at 30.
when i clean the barrel with just a patch (no cleaning product) 4 pullls the pellet accuracy at range comes right back. i think its due to dirt and deformation on the pellet as it passes through a dirty barrel.

people have many different opinions but i say clean after 80 shots

[spiredude]

i have R10 mk2 i found crossman premiers ultra magnums 14.3 gr work very well even
at 30 yards they are within 5pence peice /just a thought for you to try :-)

[Hawker Will]

Hey Guys,

Thank you all for your input! If I had carried on with the purchase of the rifle from my friend, then I would have certainly given the barrel a good clean and gone to town on it to get it sorted! But I have since bought a Daystate Air Ranger in .177. And am getting on well with it! My friend eventually sold the R10 to a gun dealer for a fraction of what I was going to pay him! Shame he didnt tell me first, it would have certainly made up for the fact it needed a bit more fettling to get it perfect again! Oh well never mind

Cheers again for your input!

Will