Leshiy .25 350mm – POI shifting
Hi,
I test all PCPs that I receive in laboratory-like conditions:
I must admit than many high end airguns and barrels failed my test (9 groups, 5 shots in each group, 50 meters). By failure I mean any anomaly in grouping during 45 shots. The mean group size should stay below 20mm. And yes, I can shoot:
http://talonairgun.com/forum/viewtopic.php?f=34&t=34742
This is what I expect from a high end airgun. My best group was 3.5mm CTC at 50 meters so you can just imagine how small my error can be.
This is how I tested Leshiy (the doors were opened during testing, no worries 😉 ):
In the beginning everything was quite acceptable at the distance of 50 meters:
Then, after maybe 30 shots the group moved 3cm to the left:
I tested that at 10 meters and POI was shifted by like 6mm. After barrel cleaning everything was spot on again. It looks like I need to clean the barrel every 30 shots or so. Something is simply wrong with that LW barrel. I may just guess that it is just me with that problem. Am I right?
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I would try and get hold of a BSA .25 barrel and get it machine fitted. Will need turning down as BSA barrels are around 15mm OD and they need to be 12mm OD etc.
I can feel a tight spot in the place where the barrel is clamped. When I remove the barrel from Leshiy then there is no tight spot.
[quote=”shooter3″]When I clean the barrel and refill Leshiy then there is no POI shift. POI shift occurs after a couple of refilling (like 30 shots). Then barrel cleaning puts the POI and accuracy back on track.
As of the tight spot, yes, there is one caused by barrel clamping system. However, it is not as tight as the choke.[/quote
Can’t see how barrel clamp would cause it to get worse after 30 or so shots. When you look down the barrel does the rifling look uniformed ?
However, I once ordered 6 barrels from different distributor’s, only 2 were fine and the other 4 had either poor crowns or suspect rifling.
The barrel clamp system on the leshiy shouldn’t cause a problem unless the steel used is of very poor quality. Which I guess is very possible.
When I clean the barrel and refill Leshiy then there is no POI shift. POI shift occurs after a couple of refilling (like 30 shots). Then barrel cleaning puts the POI and accuracy back on track.
As of the tight spot, yes, there is one caused by barrel clamping system. However, it is not as tight as the choke.
Following on, I would try the following:
– Fill the tank to 250 Bar
– Makesure the pellets used are all the same head size and weight depending on calibre.
Set the regulator to one of the following depending on calibre.
0.177 Set to 100 Bar
0.20 Set to 105 Bar
0.22 Set to 110 Bar
0.25 Set to 115 Bar
0.30 Set to 120 Bar
Fire a group of 20 shots, measure the group size, re-fill the tank to 250 Bar, repeat the process.
If the group sizes are then roughly of all the same size, repeat but increase the number of shots each time until you get to the point where the groups start to open up.
Also, one other thing with the Leshiy is unless you put the pellets in the same way each time then the heads could get deformed and give different results etc. Apparently the machining on the breach end is sometimes not great or uniformed.
PS. I think you mentioned in a previous post that there was lead build up in the middle of the barrel. THAT should not be happening and will cause your POI to get worse the more pellets you shoot before cleaning. Sounds like your barrel has a tight spot in the middle which is a fault. Most airgun barrels are poorly constructed and mass produced. Sometimes you can be lucky and get good ones and other times you get absolute rubbish. High end target shooters normally have barrels built and machined from scratch but that costs like $400-$700 for a barrel.
If the group starts to increase as the number of shots goes up then it will be a problem with the regulator/pressure dropping. Which given the size of the air volume in the Leshiy is acceptable.
What setting is the regulator on and is it the OEM one or Huma ?
That’s true but if it’s a crown issue then it should always group like a shotgun, not only after shooting 20-30 pellets.
When it comes to any type of barrel, usually the problem is associated with how the crown has been machined and to what angle. Match Target shooters with custom barrels usually have a 11 to 12 degree crown at the end.
It wont matter what make of barrel you have, if the crown is not there or badly machined, then it will group like a shotgun.
I think that deleading is not always a case. I have one LW barrel which is always spot on regerdless if it was freshly cleaned or if it shot 100 pellets.
As of the cleaning I use a patchworm-like approach.
Hey, my friend longtime ……. hum ….. …. how are u cleaning your barrel and with what ?
de-leading from over cleaning maybe ?
…… … . though it could be a trigger design issue, but …. it seems not …. .. . bi pod/mount maybe ?
Shooting with a crony in place is like a laboratory-like condition, real time ?
~ Greg
where is that range shooter? that looks lie a great place.
In principle yes but if there are issues potentially linked to “external factors affecting accuracy” because of a not free floating barrel design then they will show only on longer shooting tests like you do.
But since there is no free floating barrel Leshiy just “don’t worry and be happy” :biggrinn: .
Yeah, that is true. He has a BSA barrel selected from a couple of them as some of them were defective. That proves that Leshiy construction is capable of precision shooting.
Ok but you know Wingmaster….
Don’t know how much of his gun is “out of the box”.
:biggrinn:
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But why? I paid for a gun with a good barrel.