I have a new SAM K12. Yesterday I shot four ten-shot groups with the cylinder at 50 bar. All the groups were quite good but low, off the black. Then I fitted a different cylinder at 170 bar. The groups were now high, but in the black. Does this indicate a faulty regulator? Or what? The groups stayed consistent with each cylinder and previously this has never happened.
t.mulvey-at-auckland.ac.nz.42494.0
Change of group centre
Moderators: rexifelis, pilkguns
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Jerry LeVan
Re: Change of group centre
Hi Tom,
I think most regulators try to set the pressure to about 70BAR.
I suspect that 50 BAR is simply not enough pressure to drive the pellet without a large drop in the aim point.
--Jerry
: I have a new SAM K12. Yesterday I shot four ten-shot groups with the cylinder at 50 bar. All the groups were quite good but low, off the black. Then I fitted a different cylinder at 170 bar. The groups were now high, but in the black. Does this indicate a faulty regulator? Or what? The groups stayed consistent with each cylinder and previously this has never happened.
jerry.levan-at-eku.edu.42499.42494
I think most regulators try to set the pressure to about 70BAR.
I suspect that 50 BAR is simply not enough pressure to drive the pellet without a large drop in the aim point.
--Jerry
: I have a new SAM K12. Yesterday I shot four ten-shot groups with the cylinder at 50 bar. All the groups were quite good but low, off the black. Then I fitted a different cylinder at 170 bar. The groups were now high, but in the black. Does this indicate a faulty regulator? Or what? The groups stayed consistent with each cylinder and previously this has never happened.
jerry.levan-at-eku.edu.42499.42494
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tck
Re: Change of group centre
Can you elaborate more on your last statment, "previously this has never happened"?
What kind of AP you were using.
I uses a Morini 162EI which has a hook mount on the cocking lever. Its function is once the cylinder preasure drops below certain level, it will engage the cocking lever so that you know you are risking your grouping/score if you insist to disengage it manulally and keep on shooting.
According to someone from Morini said, the lever is set to engage at app. 70 - 80 bar which means most AP are using this preasure level to project the pellet. If you are shooting at app. 50 bar, the regulator cannot function to boost the preasure up. It can only reduce the preasure above this level, say, from 170 > 75 bar.
With some older models or CO2 APs which do not have a regulator, you can see a pattern resulting from the change of preasure. Our club has a number of FWB P-30 whcih we can observe that the grouping rises when the cylinder preasure is app. 80 - 90 bar (by app. half to 3/4 ring). Then it drops drastically when the preasure falls below
70 bar, you can actually see the pellet flying to the target and make a big tear hole instead of a clean punch.
We have made some experiments and found that each cylinder, when installed on different APs, will have different groupings. The explaination we concluded is since the tension of the spring on each AP is slightly different and so does the valve spring on each cylinder. The combination of the two will produce different values. So our competition experience is try to finish all the shoots (both sighting & competitions) without changing the cylinder and hopefully, with still 100 bar of preasure inside the cylinder. slightly
.42504.42494
What kind of AP you were using.
I uses a Morini 162EI which has a hook mount on the cocking lever. Its function is once the cylinder preasure drops below certain level, it will engage the cocking lever so that you know you are risking your grouping/score if you insist to disengage it manulally and keep on shooting.
According to someone from Morini said, the lever is set to engage at app. 70 - 80 bar which means most AP are using this preasure level to project the pellet. If you are shooting at app. 50 bar, the regulator cannot function to boost the preasure up. It can only reduce the preasure above this level, say, from 170 > 75 bar.
With some older models or CO2 APs which do not have a regulator, you can see a pattern resulting from the change of preasure. Our club has a number of FWB P-30 whcih we can observe that the grouping rises when the cylinder preasure is app. 80 - 90 bar (by app. half to 3/4 ring). Then it drops drastically when the preasure falls below
70 bar, you can actually see the pellet flying to the target and make a big tear hole instead of a clean punch.
We have made some experiments and found that each cylinder, when installed on different APs, will have different groupings. The explaination we concluded is since the tension of the spring on each AP is slightly different and so does the valve spring on each cylinder. The combination of the two will produce different values. So our competition experience is try to finish all the shoots (both sighting & competitions) without changing the cylinder and hopefully, with still 100 bar of preasure inside the cylinder. slightly
.42504.42494