PCP's....kick?

[JohnBam]

Was wondering the thoughts on this.

Zico on Wednesday noticed that he was geting a recoil effect and a POI shift on some position and support changes while trying the long range stuff.

Is this down too muzzle flip, or is there recoil in PCP's. I was quite surprised at the results Z was experiencing as I thought PCP's would be practically immune from that type of behaviour. Obviouslly at long range any change is accentuated quite a bit.

Zico was shooting a Verminator with a Wheirauch (I know i've spelt that totally wrong ) silencer.

[Arnold]

PCP's does recoil, but at 12fpe you just do not feel the recoil. This becomes more noticeable at FAC levels. When you are shooting Heavy dai sung pellets at 60FPE you definatly feel the recoil

[bigtime]

thought it was just the muzzle flip you noticed on fac guns

[Born Again]

I noticed a definate recoil on my Rapid when long range testing. I think it was more pronounced because I used Harry method of barely holding the rifle, no cheek contact and very light hold.

I'm not sure yet whether it was recoil from the hammer, from the pellet, or just the "jet" effect of the air. More testing needed.

[theboymike]

I've been thinking about this for some time, and I'm glad someone else brought it up

I've done a bit of testing off the bench rest with the S410 recently; and it definitely jumps quite a lot when fired.

The way I see it you have two sources of recoil - an initial rearward reaction force to the forward movement of the striker, with a subsiquent forward movement as it hits the valve stem.

Secondly, you have the "true" rearward recoil in reaction to the pellet moving down the barrel, and finally the "jetting" or "rocket" effect as it leaves the muzzle.

I think the striker generated movement is by far the most significant on account of its greater mass, and can be likened to the recoil of a springer - all be it on a smaller scale. Because of this it would stand to reason that PCPs are hold sensitive.

I shot a series of groups at 55yrds with the S410 a while ago; all off a soft beanbag at the forend and a jumper under the butt. The first few groups were shot gripping the rifle "as normal", the final two attempting to allow as much free movement during the firing cycle as possible.

Avg. group sizes for the normal hold were about 1.25", while those for the light hold were fractionally over 1". Perhaps a more interesting observation is that the shots within the normally held groups were all fairly evenly dispersed, while the lightly held groups took the form of tight clusters spoiled by a couple of fliers. Removing 2 shots from each of the loosely held groups drops the avg. group size to 0.6".

I think there is scope to improve these groups further since the conditions were not ideal - the hold could have been more consistent, while the scope being used was only 6x and PX'd at 35yds - so a bit of PX error could have crept in although I did my best to keep this to a minimum.

I quite fancy knocking up a resting rig to absorb any recoil, although it's a question of time and money apart from anything else.

Also we have "Rika Trainer" kit at our club for 10m training - basically it provides an on-screen trace of the gun's muzzle on the target throughout the firing cycle. I'd like to set this up on the S410 at some point to see exectly where the POI travels during firing.

Interesting stuff

[Zico]

I'm not sure yet whether it was recoil from the hammer, from the pellet, or just the "jet" effect of the air. More testing needed.

Yep, 90-95% of the muzzle flip is when firing a pellet only, once or twice I fired fresh air .. and judging solely by the feel the muzzle flip near dissapeared. The "For every reaction there is an equal and opposite reaction" principle in action here. Was using JSB 4.52, would the theoretical reduction in friction of a 4.51 diam pellet reduce it a little.. or would pellet skirt expansion nulify this?

As John says, i was experimenting with different clamping and supports to see what was produced the best results. Interestingly, a loose clamp to act solely as the horizontal hinge and ensure totally vertical muzzle flip coupled with minimal butt support proved to have the most consistant POI... same principle as a springer but only apparent at the 94 yard range we were attempting.

I attempted resting the rubber butt pad on the table and I could feel the vibration which made the groups about 5 times worse.


My very 1st 3 shots of the day (with the loose clamping and minimal support) were within aprox 1.2 inch (iirc John?) the breeze picked up a little.. I then got a few wind affected shots that took it out to about 4 iches The highlight of this 8 shot group was 3 shots through ONE ragged hole!

How effective are these muzzle flip compensators? Anyone have any definative test results? I used to consider them OTT and a bit gimicky... but not any more.

[JohnBam]

Yep, 90-95% of the muzzle flip is when firing a pellet only, once or twice I fired fresh air .. and judging solely by the feel the muzzle flip near dissapeared. The "For every reaction there is an equal and opposite reaction" principle in action here. Was using JSB 4.52, would the theoretical reduction in friction of a 4.51 diam pellet reduce it a little.. or would pellet skirt expansion nulify this?

As John says, i was experimenting with different clamping and supports to see what was produced the best results. Interestingly, a loose clamp to act solely as the horizontal hinge and ensure totally vertical muzzle flip coupled with minimal butt support proved to have the most consistant POI... same principle as a springer but only apparent at the 94 yard range we were attempting.

I attempted resting the rubber butt pad on the table and I could feel the vibration which made the groups about 5 times worse.


My very 1st 3 shots of the day (with the loose clamping and minimal support) were within aprox 1.2 inch (iirc John?) the breeze picked up a little.. I then got a few wind affected shots that took it out to about 4 iches The highlight of this 8 shot group was 3 shots through ONE ragged hole!

Spot on mate

Enlightening stuff lads, maybe the PCP's aren't as 'dead' as I thought

[onlyme]

well at 82 ft/lb in a career and a 30 grain pellet , the gun jumps a lot, the thing is the hammer in this model is that big you get recoil of the firing mechanism alone !!!! and then there is the shotgun loud crack .. but on a 12ft/lb rifle , i have only ever known a bullpup carbine with a barrel shroud to have muzzle flip that felt like a bit of recoil at the shoulder.

[dvd]

PCP's do recoil and how!
I saw a video on the tube thingy of someone firing a .50 cal pneumatic and it nearly bowled him over backwards.
I think he was not expecting that reaction from the gun.
At the other end of the scale, I shoot a 6ft lb target pneumatic rifle and I do feel a very small nudge as the pellet exits, probably jet effect more than anything else.

[jonyb]

as mentioned earlisr "every action has an opposite but equal reaction" as a pistol shooter i would suggest going back to basics i.e. stance,grip, sights,follow through.
recoil is a constant ,in a 10m,20yd pistol dicipline there is no wind so bad shots are down to bad technique. have a look at target shooting info/books to analize your faults.
the rika or scatt shooter training systems are excellent at this;if you have the facility?

[Gungeek]

Muzzle stability can be improved with a silencer fitted but in the case in question, Weihrauch silencers are very light. I found my accuracy improved, shooting an S400C with a 'heavy' Logun silencer fitted, because muzzle movement was slower and less jumpy with the extra weight at the front. Regards .... Geek

[flims]

ok with my 57ft/lb shooting 31grain barracudas, recoil is felt. my groups are much better when i hold the gun snug and fit rather than light recoil and i use a small sand bag underneath the butt. what happens when i shoot long distances is usually this and i know right away that i called the shot incorrectly. When i squeeze the trigger the reticle jumps and does not return to the original Point of Aim thus i mark it on the logbook as an incorrect shot. in these cases the reticle usually returns to place where the pellet has hit further showing that the shot was not taken properly.

As soon as i squeeze the trigger the rifle butt moves slowly backwards and downwards since the stock is slanting thus sometimes i do throw one or two shots above the group that had formed so nicely. i regret that i never had a stock made with a flat butt like those used on F class because the slanting stock is not good enough for the precision i try for and when you do everything perfect, you read the wind, you dial the correct elevation, recheck the distance and then blow your shot high because of this, it is definately frustrating. i might get a monopod to sort this problem out really that waythe gun would notmove downwards.

[Rapidnick]

Newton's Third Law of Motion (every action has an equal and opposite reaction) applies to precharged air rifles as it does to everything else. The reason you don't feel it at low power levels is that it is so small. it is related to the energy in the pellet so as pellets get heavier and MV gets faster the effects begin to be noticed. In .22 I notice it around 40 ft lb with 21.4grain Bismags. In .25 I certainly notice 31 grain Baracudas being spat out of the rifle at 55 ft lb. In .177 the only time you would notice it would be when using very heavy pellets at 30+ ft lb.

[RobF]

you certainly can feel it at lower power... I can notice the recoil of my 6ft/lb 2002 vs a 6ft/lb steyr fitted with a recoil damper...12 ft/lb rigs are noticably more jumpy in comparison, even the so-called dead ones

[squirminator]

My .22 FAC HW100T kicks a little more than the standard UK version.

I've closely compared the "view-through-the-scope" rat hunting videos posted on YouTube by a guy called "snypercat" (you can look these up - worth seeing). I know that he is UK based.

I cannot quite match his steadiness during shot release with my own HW100T rifle. I get a noticeable (albeit very small) jolt whenever I pull the trigger.

My rifle is putting out about 25-29 ft/lbs - his is below 12 ft/lbs.

It makes perfect sense if you think about it - Newton was right

I'd imagine that his groups are slightly tighter too.