Calling all 25 cal marauder REGULATED guns

[HighAltitudeAir]

Ok, great thanks Mark. I was hoping that was the case. I working on the Armada now and hoping I would not have to wait on a depinger.
CH

[GoneShootn]

Here's my situation, so far ...

Rifle:   Marauder .25 synthetic stock

Mods:
Huma regulator with gauge port, set to 150 bar
Drilled valve and barrel ports to 11/64"
Hill lightweight valve spring
Hill 262 hammer spring
Hill high flow transfer port
Hill lightweight hammer

When the rifle is filled to 3000 psi, the rifle gauge shows 2350 psi.

The first thing I noticed was a much better sound. No more "buh-loop" as with stock setup. Just a  nice crisp, but quiet "BAP". Tim Hill recommends no more than 2.0 turns in on the hammer spring in going for a 40/40, but I had to go all the way to 4.0 to get to the 40 fpe range, or an average fps of about 845. At that point the cocking effort is a bit more than I would like, and I have to be careful to not double-load.

One thing I am going to have to address is that the hammer spring setting tends to drift down as the rifle is fired. That was an issue with the first shot in the below string, so I had to adjust back to 4.0, beginning with shot 2. By the end of the string, however, the hammer spring had drifted back down to 3.5 turns in.

So, what I have done seems to have improved the performance of the rifle, but I am a long way off from a 40/40 tune, and that is disappointing. Not that I'm not there, as I didn't expect to be, but that I seem to be so far off. The string is below. I would appreciate any thoughts or suggestions.

-------------------------------------
1.   821 (HS had slipped, adjusted back to 4.0)
2.   842
3.   838
4.   839
5.   849
6.   839
7.   842
8.   846
9.   852
10.   846
11.   845
12.   848
13.   845
14.   841
15.   850
16.   848
17.   845
18.   851
19.   849
20.   839 (off reg)

Shots 20-32:  839 fps down to 830


For shots 2-19
--------------------
High   851
Low   838
ES   13
ES%   1.54
Avg   845

End pressure 2200 psi

[shorty]

Jere,
That's alot of Hill parts in that gun.... My biggest question for you is what did Tim Hill say about it ?

My thoughts,
Everything looks great there to do the 40/40 but you can use some pixy dust. On the valve, did you open the throat to a minimum of .25" and no greater than .26" ? Even though you opened the port to 11/64 (.171") the valve still needs to breathe down stream to the HPA.
Hogging the entrance of the valve to .5" nearly all the way down to the poppet seat helps with the available plenum.

Lastly, opening the exit port,transfer port, and barrel port to .187" helps much better. To see the real results from a .187" porting, you should truly pull the shoulder back on the bolt probe.

If you were to do all that, I think you can get the 40/40 tune at just under 2000psi ( 1950 psi ).

It's a shame that no one sells a true guaranteed drop in 40/40 tune for a reasonable price yet.

[GoneShootn]

Jere,
That's alot of Hill parts in that gun.... My biggest question for you is what did Tim Hill say about it ?

Says sounds like I need a higher flowing valve assembly to get there.

My thoughts,
Everything looks great there to do the 40/40 but you can use some pixy dust. On the valve, did you open the throat to a minimum of .25" and no greater than .26" ? Even though you opened the port to 11/64 (.171") the valve still needs to breathe down stream to the HPA.
Hogging the entrance of the valve to .5" nearly all the way down to the poppet seat helps with the available plenum.

No, I didn't. Maybe because I didn't know to do that, and maybe because I don't know what the throat is. :-) Would that require a mill?

Lastly, opening the exit port,transfer port, and barrel port to .187" helps much better. To see the real results from a .187" porting, you should truly pull the shoulder back on the bolt probe.

I only went to 11/64" (.169") because Tim Hill said, "I don't drill the stock valve body more than .161 i.d..  I don't want to chance a bent valve seat from the constant high pressure." I know that he used to sell modified stock valves, so I figured it was good advice.

If you were to do all that, I think you can get the 40/40 tune at just under 2000psi ( 1950 psi ).

It's a shame that no one sells a true guaranteed drop in 40/40 tune for a reasonable price yet.

Thanks for the input.

[shorty]

Jere,
I am sorry If I came across a little difficult. It's just because It looks like you spent a good bit of change to get a 40/40 tune.

The throat is just behind the poppet. You can use a drill bit but it is very challenging to keep the valve seat neat and clean for a good seal. If you do a drill bit make sure you "seat" the poppet well with a light abrasive such as car polish.

I am sorry again as all I did to get the 40/40 is all homemade parts except the reg.

The valve was hogged to the valve seat to .5" , the throat is .25" , I opened up the valve cap to .475" , made a new poppet spring to fit valve body/poppet head, drilled ports to .187", pulled back bolt probe, ran a short stiff spring.
The first time I did this was with a battery powered drill and vise.

Just doing that is good for 55fpe for 16 shots with 33.95's and just over 40 shots with 25.39's at 40 fpe.

Sorry if you took my comments the wrong way

[GoneShootn]

Jere,
I am sorry If I came across a little difficult. It's just because It looks like you spent a good bit of change to get a 40/40 tune.

The throat is just behind the poppet. You can use a drill bit but it is very challenging to keep the valve seat neat and clean for a good seal. If you do a drill bit make sure you "seat" the poppet well with a light abrasive such as car polish.

I am sorry again as all I did to get the 40/40 is all homemade parts except the reg.

The valve was hogged to the valve seat to .5" , the throat is .25" , I opened up the valve cap to .475" , made a new poppet spring to fit valve body/poppet head, drilled ports to .187", pulled back bolt probe, ran a short stiff spring.
The first time I did this was with a battery powered drill and vise.

Just doing that is good for 55fpe for 16 shots with 33.95's and just over 40 shots with 25.39's at 40 fpe.

Sorry if you took my comments the wrong way

No, no, no! Just the opposite. I very much appreciated your suggestions. That's exactly what I asked for. I'm not sure what I said to make your feel otherwise. I surely didn't mean to, so I apologize for my obviously poorly worded reply. Where I said, "Maybe because I didn't know to do that, and maybe because I don't know what the throat is. :-)", I was making fun of my own ignorance when speaking to someone much more experienced. So, just lame humor perhaps?

[Bigragu]

Jere, put a hill peek striker on that hammer. You won’t believe how much that quiets down the gun. I already had Tim’s moderator installed awhile back, but recently installed the peek striker on his hammer, and I had to check the velocities it was so quiet. I got worried that I was shooting at around 500 FPS it was that quiet. Just a small PFFFTTT! Is all I hear now.

I’m averaging 841 for like 36 shots, using the 26 grain H&N crow magnums on my 25 cal. ChairGun says I’m at 41 ft lbs. Just did this today. 2 turns CW on that hammer spring adjustment is all.

[Bigragu]

And, I want to add, that Shorty not only knows his stuff with the tweaking of these marauders, but he’s very helpful thru PM’s also.

At least with me he is, lol!!

[GoneShootn]

And, I want to add, that Shorty not only knows his stuff with the tweaking of these marauders, but he’s very helpful thru PM’s also.

At least with me he is, lol!!

What valve are you using to get there?

[Bigragu]

And, I want to add, that Shorty not only knows his stuff with the tweaking of these marauders, but he’s very helpful thru PM’s also.

At least with me he is, lol!!

What valve are you using to get there?

I am using Tim Hill’s valve. It came with his premium kit. Basically everything you already have, but with his Audrius regulator and his valve.

The one thing I’ll never quite find out, is when I first installed that kit I was in the high 860’s to low 850’s for like 26 shots. An extreme spread of about 15 psi, and only two turns on the hammmer screw.

Then I foolishly watched a video on you tube, where a guy runs a ball hone to buff the pressure tube up. When I say foolishly, I’m meaning I should have left everything alone. I like the fact that I de burred all the slots and hole in the pressure tube, and got it to a mirror finish on the inside.

But since then, for the life of me, I cannot get up to the 860’s anymore for that long a string. 856 FPS, if I recall, was what I was averaging with that string.

 Oh, well. I’m so close to that 40/40 tune averaging 841, I’m just going to say I achieved it, lol

[triggertreat]

Here's a 40/40 tune I did, but was running 41 fpe for 35 shots instead, close enough.  The notes at the bottom in the graph show I was using the Hill valve and also the ports Tim was talking about, but I was also using a Hill TP at .161 so I was restricted at that point and still made it.  The reg was set 1950 psi as Tim talked about as well.  hope this helps.

[Bigragu]

Keith, thanks for posting that. I believe I saved that spreadsheet in my photos for to use as a guide

[Thane]

Some progress with mrod .25 strings 25.39gr with Huma set at 1800, starting at 3100psi.

Red is my 40/40
Purple is a power 34gr  string  30/47
Blue for 55/38 near the valve lock point and wilder ES
Yellow was an attempt at reducing velocity with transfer port restriction of power tune only, poor shot count good ES.

Huma is the only purchased mod the rest came from the great contributions here using a small machine lathe and mill. Turned an MDS hammer with bronze insert, FFH with a stiff spring puts these strings within 3/4 of a turn preload.
Stock gen II valve, stock valve spring, .187 TP, 1/2 Bore, stock valve seat, .266" behind seat and ported. Turned bolt probe to 0.1" and shoulder turned back. Plastic line TP.

[GoneShootn]

What valve are you using to get there?

I am using Tim Hill’s valve. It came with his premium kit. Basically everything you already have, but with his Audrius regulator and his valve.

I considered that but wanted to see how close I can get this way first.

The one thing I’ll never quite find out, is when I first installed that kit I was in the high 860’s to low 850’s for like 26 shots. An extreme spread of about 15 psi, and only two turns on the hammmer screw.

Then I foolishly watched a video on you tube, where a guy runs a ball hone to buff the pressure tube up. When I say foolishly, I’m meaning I should have left everything alone. I like the fact that I de burred all the slots and hole in the pressure tube, and got it to a mirror finish on the inside.

But since then, for the life of me, I cannot get up to the 860’s anymore for that long a string. 856 FPS, if I recall, was what I was averaging with that string.

 Oh, well. I’m so close to that 40/40 tune averaging 841, I’m just going to say I achieved it, lol

That's seems to defy logic. Still, you got there.

[GoneShootn]

Here's a 40/40 tune I did, but was running 41 fpe for 35 shots instead, close enough.  The notes at the bottom in the graph show I was using the Hill valve and also the ports Tim was talking about, but I was also using a Hill TP at .161 so I was restricted at that point and still made it.  The reg was set 1950 psi as Tim talked about as well.  hope this helps.

Nice string! Also great spreadsheet/graphic. Thanks for posting it.

[GoneShootn]

Some progress with mrod .25 strings 25.39gr with Huma set at 1800, starting at 3100psi.

Red is my 40/40
Purple is a power 34gr  string  30/47
Blue for 55/38 near the valve lock point and wilder ES
Yellow was an attempt at reducing velocity with transfer port restriction of power tune only, poor shot count good ES.

Huma is the only purchased mod the rest came from the great contributions here using a small machine lathe and mill. Turned an MDS hammer with bronze insert, FFH with a stiff spring puts these strings within 3/4 of a turn preload.
Stock gen II valve, stock valve spring, .187 TP, 1/2 Bore, stock valve seat, .266" behind seat and ported. Turned bolt probe to 0.1" and shoulder turned back. Plastic line TP.

Thane - It looks like you are trying to post an image, but I'm not seeing it. Anybody else seeing the image?

[triggertreat]

Here's a free spreadsheet a made to share if you need one:  Click here to download the free spreadsheet

[GoneShootn]

Here's a free spreadsheet a made to share if you need one:  Click here to download the free spreadsheet

Yeah, I did need one. Thanks.

[Thane]

Fixed the attached image with my strings. Really like that spread sheet, will import some string data!

Nope, password protected spreadsheet...

Got it, stuck some strings in, very nice breakdown of data.

[triggertreat]

Fixed the attached image with my strings. Really like that spread sheet, will import some string data!

Thanks!  I see you have some very nice strings there.  Your spreadsheet does compare more strings at a time.  My spreadsheet does have a place to store some strings for future reference plus the three graphs so 12 in total, IIRC.  I tried to keep the spreadsheet simple for the novice, but still have a few features too like comparing three strings at once with just a tab click.  Just paste your FPS string in the FPS column in any of the three graphs.  Just highlight, right click and select clear content for any past string data you want to remove.  There are some locks on certain cells to keep the formulas intact and prevent issues when using it.


I did create a much more advanced spreadsheet that is much more automated, but I don't think it's for everyone.  It will store 80 strings currently and automatically puts the full string and all associated notes and data in any of the three spreadsheets I select along with correcting any overlapping data.  Still working on more features for it too, just another hobby for me.  I like storing strings from the forum if all the data is provided.