PCP Woes - Too much pressure, too much power

[LDP]

Reducing the power is what increases the shot count, not using a reg. to do so.... You can clearly see that in the chart I posted.... I didn't misunderstand, I merely wanted to emphasize that is the power reduction that increases the shot count....

Bob

Yes that is true lowering power on a non reg pcp will increase shot count but you are still working with a lower amount of air at a lower psi fill than the regulated pcp. With the reg you would be working off a 3,000 psi fill not 2,000 psi. So are you saying a non reg pcp set up for a starting fill of 2,000 psi is going to have the same shot count as a pcp regulated to 1700 - 1800 psi or lower and filled to 3,000 psi?

[redlined_b16a]

What about a regulator.Still pump to 2900 psi
Set regulator to 1500 psi.
Get plenty of accurate shots in the lower fps range you want.

[ezman604]

The problem that I am having is that it is a beast to fill 2900 PSI with a hand pump, and the 900 FPS velocity is a bit much for back yard pesting.
*Using a 2000 PSI fill pressure will enable me to more easily fill with a hand pump, or use an inexpensive SCBA tank from the local dive shop.

Would it be easier to get a Maximus dialed down to 700 FPS than converting the Marauder to shoot at 2000 PSI?
What transfer port size should I start with to lower the velocity?

Thanks in advance!

Some keep overlooking this part...

[rsterne]

Of course not, Leland.... Filling to 3000 psi will give a huge shot count advantage compared to filling to only 2000 psi.... and filling to 4500 psi (in an appropriate gun) will increase that even further.... However, we are talking apples and oranges.... Yes, if you tune an MRod to shoot at 16 FPE at 1200 psi, using a regulator, and fill it to 3000 psi, you will get huge shot count at low power.... However, if you are using a Disco, which is limited to a 2000 psi fill, and tune it unregulated to 16 FPE and get 40 shots (per my graph).... you will be hard pressed to get that same power and shot count with a regulator installed....

Sorry if I misled the OP with my statements.... Regulated PCPs are absolutely the best way to get low to medium power in PCPs, provided you have a large enough reservoir (both pressure and volume) to feed them.... An MRod, properly tuned to 16 FPE by using a regulator and the appropriate other changes, would be a great choice.... providing filing to 2900-3000 psi is something the OP wants to do.... If he really wants to fill to 2000 psi, there may be a better alternative....

Bob

[ackuric]

Prior to regulating I could only achieve a MAX of 32 shots @ 40 fpe within around 3% ES.

After regulation I could achieve easily 40 shots @ 40 fpe with 2% ES or better.

Yes regulators CAN increase shot count, but in the above scenario my EFFICIENCY did NOT increase...I disagree wholeheartedly with Bob stating regulating gains NO shots...

I have my .25 cal tuned at 1950 psi regulated shooting anywhere from 12-60 fpe, the 12-15 fpe tunes I use in my backyard @ 20-30 yards and have PLENTY of knock down power and accuracy is always better than 1 moa.

With the proper adjustments you could tune a marauder to do 5-20 FPE in any stock caliber from 1000-3000 psi if one desires...just gotta find the right balance in hammer weight/spring and tp sizing to do it well.

[LDP]

Bob we were talking about the same thing just different angles. Yes we agree on all the points

The problem that I am having is that it is a beast to fill 2900 PSI with a hand pump, and the 900 FPS velocity is a bit much for back yard pesting.
*Using a 2000 PSI fill pressure will enable me to more easily fill with a hand pump, or use an inexpensive SCBA tank from the local dive shop.

Would it be easier to get a Maximus dialed down to 700 FPS than converting the Marauder to shoot at 2000 PSI?
What transfer port size should I start with to lower the velocity?

Thanks in advance!

Some keep overlooking this part...

Im not overlooking that part. Im trying to give the op an alternate fix so he doesnt have to sell his mrod. With the large shot count he would gain by using his mrod regulated down there would be less pumping and more shooting. The OP could still just pump the mrod to 2,000-2100 psi. If the mrod only needed 1500 psi as a reg setpoint that would be a very viable way to get his low power tune, great shot count and keep his mrod while still having flexibility to go up if he ever gets a tank.

[moorepower]

I'll offer up MY opinion. So you can take it with a grain of salt or sugar, whichever. LOL
I love the Mrod platform. It is so very versatile and so many aftermarket goodies available. And I build my own stuff for it too. But it is a 3,000psi airgun. Yes, you can dial one down to make it a 2,000psi airgun. But for me, it's like buying a Porsche and installing a governor to keep the speed down.
I would suggest getting an airgun more suited to your purpose and adjusting from there. Like a Disco or Maximus. Or an S200. There are several more suitable choices in that power range and air reservoir capacity.
Whatever you choose....
SAFE & Happy Shooting!!!!
Dave
 

If he didn't already have the Mrod I would agree. Detuning is not that hard. Or put in a regulator set for 1200psi, adj hammer spring and striker to get velocity needed and open up the 3000psi bottle and fill. Who cares if it does not keep filling to 3000 psi. Repeat until tank is at 1200 and refill for $8.

[datilD]

Thanks again for all of the replies.  I have been doing a lot of reading/research based on the information that everyone provided.  One thread leads to another, and another...  After weighing the costs and level of mods required to get an AG where I want it, I have decided to sell the Marauder and get a Maximus.  I will call it the Minumus Maximus.     I'll be digging through a lot of Disco mod threads, and working on efficiency and a consistent shot string (after I am sure that the Maximus is accurate and functioning well).  If time allows, I'll try to document the process.

[Taso1000]

Derek,

Don't forget that there is also a Maximus .177 Euro that is tuned for 12 fpe from the factory.

Taso

[makoda]

I did this very thing.  Had bought a war tss and mds hammer as well as a hammer forged barrel.  Detuned it by using only the heavier spring in the tss.  Was shooting from 650 to 675 and back down to 650fps.  Very little change in poi and I shot ten magazines through it the other day killing 102 squirrels.  that was shooting from about 1850psi down to I think 850.  That's the most I pushed it.  It does have a bit of a shot curve shooting that low of fps but it worked well for birds and squirrels.  I would say it was a good 50 yd gun with shots out to 75 if the wind wasn't too bad.

Also I should add I am shooting the jsb 13.43 in .22

I just did today bring it back up to a range of 685 fps to 720 fps.  I did notice the power curve not being as flat as the lower tune and I am getting less shots (guessing around 70), but it is a touch snappier, so the wind doesn't push it as much and it did flatten the shot curve a little.  Shooting a little farther should be possible.

As for noise this was as high as I could go before the noise took a jump in sound, probably due to the hammer bouncing on the valve.

Its getting late and it been a long day so this might not make much sense, so sorry in advance.
 
All in all I think it may have been better to leave it where it was, but I am going to shoot with this for a while and see how it does.

[datilD]

Derek,

Don't forget that there is also a Maximus .177 Euro that is tuned for 12 fpe from the factory.

Taso

I wanted to stick with a .22 for better knockdown power for the rodents.  I did see that they make a .22 Euro @ 650 fps.  I can't find any review on the .22 Euro (plenty for the .177, though).  If it had a flat shot string, it would be worth considering.  The threaded end on the barrel is a plus, too.

I did this very thing.  Had bought a war tss and mds hammer as well as a hammer forged barrel.  Detuned it by using only the heavier spring in the tss.  Was shooting from 650 to 675 and back down to 650fps.  Very little change in poi and I shot ten magazines through it the other day killing 102 squirrels.  that was shooting from about 1850psi down to I think 850.  That's the most I pushed it.  It does have a bit of a shot curve shooting that low of fps but it worked well for birds and squirrels.  I would say it was a good 50 yd gun with shots out to 75 if the wind wasn't too bad.

Also I should add I am shooting the jsb 13.43 in .22

I just did today bring it back up to a range of 685 fps to 720 fps.  I did notice the power curve not being as flat as the lower tune and I am getting less shots (guessing around 70), but it is a touch snappier, so the wind doesn't push it as much and it did flatten the shot curve a little.  Shooting a little farther should be possible.

As for noise this was as high as I could go before the noise took a jump in sound, probably due to the hammer bouncing on the valve.

Its getting late and it been a long day so this might not make much sense, so sorry in advance.
 
All in all I think it may have been better to leave it where it was, but I am going to shoot with this for a while and see how it does.

   I am stuck on the "killing 102 squirrels" part.  I thought that I had a problem with pests. 

On a completely unrelated note, I am using a chipper dipper in conjunction to high speed lead poisoning for chipmunk elimination.  https://hubpages.com/living/Problem-with-chipmunks-Build-a-chipper-dipper  I got 5 chipmunks the first day that I used two chipper dippers in the yard.  Subsequent uses have only caught a single chipper in each.  I pretty much get a chipmunk every time that I put it out, and it is a set and forget type trap.  With the AG eradication, I have to keep a lookout for the pests.  They keep making new holes, and it is getting harder to monitor all of their locations. 

[Taso1000]

My mistake.  I thought you were looking for .177.  800 fps is flatter than 650 fps though. 

177 should be fine for rodents.  You also don't want pass throughs from the .22.  If you were shooting beyond 50 yards or raccoon size critters then I would definitely go to .22 or even .25.

Taso

[AlanMcD]

Derek - you should re-read what Matt said in post 29 . . . but don't focus on the purchased parts.  The best would be to do it with the TSS and MDS (or an even lighter hammer), but they are not needed.

What he did is great, but you can do much the same with stock parts by taking out all the spring pre-load (the 1/4" adjuster at max counter clockwise), shortening up the stroke (the 1/8" adjustment in the hammer being about 7 or 8 full turns clockwise, after having been adjusted to full stop counter clockwise).  That will minimize your hammer energy and thus dramatically lower your fill pressure.

The work on restricting your transfer port setting in the valve to bring the power down to where you want it. It will take a bit of playing, but you will likely end up with a tune that gives you at least 4 mags on a fill of about 2100 psi or so.

That way you keep the Marauder (a much better gun), and are well positioned to go the other way in power and tune if you get an air tank or compressor in the future.

[makoda]

These were ground squirrels at a neighbors property.  I was amazed at how many there were as well when I pulled up and the ground was moving.  I actually missed 4 shots out of ten clips but got 4 doubles and one triple(pretty good for only 12 ft/lbs) for 102.  I will say though I doubt I could have done that with my FX streamline at full power due to noise.   When I shoot at pests with it although very quiet they will still hear it and others around it won't stay for long.  The marauder turned down literally only makes the sound of the hammer strike so unless your right next to it you can't hear it. 

These squirrels had already been shot at by the land owner with a crosman pumper pellet gun and were conditioned to shot noise (I could understand his frustration with his setup when there were so many and each day he could only get a couple), because when I did go back one other time to pick up any left over I took both guns and the fx would send them all running for their holes but the marauder wouldn't.  I definitely see that as why I was so effective.  In fact one area had 5 within about 3 ft of each other and none ran while I picked them all off, the last one was getting nervous trying to figure out what was going on.

Also see what alan just posted about the tss and mds, yes I originally bought these for full power tuning, but after having two guns at almost the exact same settings, I decided to try something else with the marauder.  The way it is set up now would be no different than just doing what he said.  And like he said if you decide this is not what you like later on then its easy to change back.

[datilD]

Well, I sold the Mrod.  I ordered a Maximus and a load of parts to build the gun that I had anticipated when I got the Mrod.  (Mrod trigger and spacer, Challenger transfer ports and finger guard, extra barrel band and a bunch of screws and seals).  I also ordered a Neil Clague moderator.  Ouch!  But, from all accounts that I have read, it will completely quiet the report.  Especially after I get it down in the 12-14 fpe range. 

I hope to be able to do a build log on my progress in putting the Maximus together.  It will be an ugly gun, but should perform like a champ for pest elimination and target shooting.  In case you are wondering why I didn't do this on the Mrod, it was about money.  I spent more on the Mrod than I was comfortable with in the first place, and did not want to sink a few hundred more into it to get it to where I needed it.  The funds from the Mrod completely covered the Maximus, mod parts and moderator.

I am picking up a few drill bits in the gauges Bob shows on his graph, and will drill the Challenger ports to lower the fpe and increase shot count.  I also have a Challenger power adjuster that I'll install.  If I can get my Chrony to work properly, I'll be documenting the shot strings along the way, too.  I won't be able to do the professional graphs that Bob does, though.

Thanks again for all of the tips and advice!

[triggertreat]

It would be interesting to hear you're experiences and comparisons between the Mrod and the Maximus.  Glad you are going with what your gut is telling you and what you think is best for your own needs.

[oenomaker]

Without doing any serious mods like drilling out the transfer port or installing a reg I could easily adjust my Marauder down to the high 600fps with just a WAR TSS and a MDS hammer.... I only put two magazines through at that setpoint just to see how many shots I would get, but it wasn't want I needed for my uses so I tuned it back up to 875fps at 2800psi.  All I'm saying is that it can be done without a regulator, you just won't have the super consistent shot string as the reservoir pressure goes down. 

[triggertreat]

Without doing any serious mods like drilling out the transfer port or installing a reg I could easily adjust my Marauder down to the high 600fps with just a WAR TSS and a MDS hammer.... I only put two magazines through at that setpoint just to see how many shots I would get, but it wasn't want I needed for my uses so I tuned it back up to 875fps at 2800psi.  All I'm saying is that it can be done without a regulator, you just won't have the super consistent shot string as the reservoir pressure goes down.

I beg to differ.  Just look at my unregulated .22 Synrod signature with TSS and MDS.  31 shots @ 1.6% ES at ~30 FPE.  Much flatter (so far) than my regulated .25 Synrod.

[oenomaker]

Without doing any serious mods like drilling out the transfer port or installing a reg I could easily adjust my Marauder down to the high 600fps with just a WAR TSS and a MDS hammer.... I only put two magazines through at that setpoint just to see how many shots I would get, but it wasn't want I needed for my uses so I tuned it back up to 875fps at 2800psi.  All I'm saying is that it can be done without a regulator, you just won't have the super consistent shot string as the reservoir pressure goes down.

I beg to differ.  Just look at my unregulated .22 Synrod signature with TSS and MDS.  31 shots @ 1.6% ES at ~30 FPE.  Much flatter (so far) than my regulated .25 Synrod.

But you don't want to only fill to 2000psi... I doubt it would work so well at those lower pressures.

[cidd]

buy a scuba tank for $200 bucks and get it filled at you local scuba store for $5 or check you local scuba store and see if you can get a used one at a good price