Wondering if anyone else has seen this, or has any idea why it would be the case. I was doing a routine Chrony check on my RAW tonight and I noticed that every time I changed out the magazine the first shot out of the mag the velocity drops by an average of 5 FPS. I ran 6 mags through and 5 out of the 6 the first shot dropped by at least 5 PFS below the average. The extreme spread on 72 shots was only 12 FPS, so still very good even with the first shot drops. It drops below 10 FPS if I exclude the first shot out of each mag from the calculation. Seems totally bizarre to me. Anyone else seen this or have any idea why it would be the case?
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Noticed something strange tonight with my RAW HM1000
- Thread starter tsp3355
- Start date
Yes it seems to be relatively normal. Mine has done that since new and my regulated .22 Marauder does that as well. It seem the regulator creeps a bit in the time it takes to load a mag or if its been sitting for a bit. Not an issue unless you are shooting for tight groups at longer ranges. If you take more time between shots it may even out a bit as well.
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I don't believe the reg is leaking, I think I will shoot Martin a note and ask him if this is normal.
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Are you shooting from a bag or vise?
It is very easy to get a difference of say 5fps just from the rifle not being in the exact same position everytime. A small difference in distance , or Angle is the most likely cause.
John
It is very easy to get a difference of say 5fps just from the rifle not being in the exact same position everytime. A small difference in distance , or Angle is the most likely cause.
John
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Could be the magazine damaging the first pellet, it is a self indexing magazine right? There is always the risk of those kinds of mags to damage pellets due to how they work, try single loading a shot string and compare
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Mags are self indexing. If that is the cause, it is happening with two different magazines, so might be a design issue. That would also explain why 30 Cal is seeing the same thing. Spy, I always use a gun vise when using the Chrony.
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I'm pretty sure that its an established norm that regulators need more than a couple seconds to equalize fully from one shot to the next. When I put the Airgun Exporter regulator in my .177 Marauder it had suggested settings for either fast settling, or waiting for more consistent pressure. I may not have said that quite right. I set it for fast settling, but if I wait 15 seconds between shots it still shoots at a more consistent speed from shot to shot.
The drop you see may simple be that when it equalizes fully the pressure is just a hair more than your valve, hammer etc setup is design to be optimum at. Regulated guns are subject to the same forces as unregulated guns in that respect, but because the pressure is close to the same you don't usually see the curve until you drop off the regulator.
My .177 Marauder actually comes up just slightly as it come off the regulator before it starts to drop.
The drop you see may simple be that when it equalizes fully the pressure is just a hair more than your valve, hammer etc setup is design to be optimum at. Regulated guns are subject to the same forces as unregulated guns in that respect, but because the pressure is close to the same you don't usually see the curve until you drop off the regulator.
My .177 Marauder actually comes up just slightly as it come off the regulator before it starts to drop.
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its common on all PCP's when you release air that's under pressure the temperature changes and when your loading your mag the air temp is stabilizing witch also interferes with the pressure so when you take the first shot of your new mag the air temp and pressure is different from your last shot from you last mag. Am I making sense? its been a long day.
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I went outside today with the Chrony and got some really big swings. Prior to today, I've been doing all my testing inside using LED puck lights, but now I'm not convinced those lights are providing accurate readings so I just ordered the light kit for my ProChrono Digital. Should be here before next weekend, so I will run some additional shot strings with the new light kit. I will also try waiting at least 15 seconds between shots to see if that makes any difference.
I did send a note to Martin at RAW. I will let you guys know what he has to say.
I did send a note to Martin at RAW. I will let you guys know what he has to say.
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Practically, no it's not a big deal at all. An ES of 12 on 70 shots is better than good in my book. I just thought it was really weird that it was happening on the first shot from each magazine. Now its bugging the hell out of me till I figure out why it does that 
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I also noticed something very similar chronying my un-regulated FX Indy, and in my case, I think hammer spring set (fatigue after being cocked for some time) was the culprit, as nothing else would expliain the phenomenon.
Could it be that between changing the magazines you keep the hammer cocked for a bit longer, thus 'tiring' it a tiny bit? Should be easy to test.
Could it be that between changing the magazines you keep the hammer cocked for a bit longer, thus 'tiring' it a tiny bit? Should be easy to test.
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LOL! it sucks being a perfectionist sometimes eh? I have not had any "real" issue with mine. It doesn't have significant impact on real world use.
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I thought about the hammer spring too, but it takes less than 10 seconds to switch mags. I doubt that is the culprit.
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Sometimes the regulator behaves this way if the orings are leaking.
@tsp3355 have you adjusted the hammer spring or is it at stock setting ?
@tsp3355 have you adjusted the hammer spring or is it at stock setting ?
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Did a little more testing with this rifle today after picking up an OEM light kit for my CE ProChrono. Definitely get more consistent results with the OEM light kit than what I was getting with the LED puck lights from Lowes. I also found that the rifle was shooting slower than I thought. For some reason the LED puck lights read about 10 FPS faster than the OEM light kit. No idea why, but my rifle was only pushing the JSB Kings at 814 FPS avg so I adjusted the HST to put it back up to 835 FPS and it seems to be working fine now. I'm not sure if the hammer spring lost some tension as the rifle broke in, or if the adjuster is backing off over time for some reason. Will have to keep an eye on the velocity for a bit and see if backs off again, but at this point I'm assuming it was just the spring breaking in. Increasing the velocity also seems to have stopped the first pellet out of the mag velocity drop I was seeing. Updated shot string after the HST adjustments below.
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