Benjamin 25 caliber Marauder Range Session

[Cbourbeau32]

Hello, purchased my 25 Marauder back in February but just recently started to mod/shoot it a little bit.

I added an 18 lb hammer spring from Jefferson State and a hammer denounce device from AOA.

I got the following shot strings in the attached screenshots, using JSB 25.39 and 33.95 with four and a half or five turns in on the hammer spring (wouldn't cock with any more turns in).

Starting pressure was 3000 on both and ending pressure was 2150 on the 25.39 after 23 shots (first shot was a double load). Ending pressure was 2400 on the 33.95 (one shot was a duplicate (790) and was lost during an incoming call while using the chronograph app) so it only shows 15 shots.

Does anyone have shot strings using a bone stock set up using one or both of these pellets?

 

[3Crows]

They are both declining strings, not a Bell curve.

Not sure what the AOA debouncer is. I am using either the JSAR TSS/SSG or the AGR free flight hammer assembly. Or a home made version thereof. But my rifles are quite modded so I cannot help with your shot strings.

 

[Dairyboy]

I would back off the hammer spring 1 turn and then see. It's been many years since I played with a Mrod and usually was in .22. But I think around 16 shots at 4% ES is average for a .25. What are you looking to accomplish. High power or shot count?

 

[Cbourbeau32]

I would back off the hammer spring 1 turn and then see. It's been many years since I played with a Mrod and usually was in .22. But I think around 16 shots at 4% ES is average for a .25. What are you looking to accomplish. High power or shot count?

I'm looking for high power, I think I'll leave it alone for now and see how accurate it is with these two pellets and JSB Hades before I make any changes.

 

[3Crows]

I would back off the hammer spring 1 turn and then see. It's been many years since I played with a Mrod and usually was in .22. But I think around 16 shots at 4% ES is average for a .25. What are you looking to accomplish. High power or shot count?

My closest to stock non-regulated M-Rod is a Gen 1 (but still is modded). Increased valve bore, AGR FFH/SSG, AGR Hybrid tube, bottle brush depinger, Teflon TP, barrel port at .161 and I get 24 shots at 44 fpe average that is a nice flat curve that drops a little right at the end. I usually shoot Hades or the JSB Exact 25.4 in this rifle.

But for contrast, one of my regulated rifles:

 

[Dairyboy]

My closest to stock non-regulated M-Rod is a Gen 1 (but still is modded). Increased valve bore, AGR FFH/SSG, AGR Hybrid tube, bottle brush depinger, Teflon TP, barrel port at .161 and I get 24 shots at 44 fpe average that is a nice flat curve that drops a little right at the end. I usually shoot Hades or the JSB Exact 25.4 in this rifle.

But for contrast, one of my regulated rifles:

Impressive for a unregulated gun. Also the regulated one is nice. I did years back a 40 shots at 40fpe tune on a regulated .25. Was a nice gun.

 

[Kpac]

Oh crap higher power is easy i dont shoot much at super high power but i ripped outball my insides and replaced with hill 7075 aluminum debouncer springs port everything my can hit 100 plus fpe easy but i shoot lighter heres a pick

 

[Kpac]

Oh crap higher power is easy i dont shoot much at super high power but i ripped outball my insides and replaced with hill 7075 aluminum debouncer springs port everything my can hit 100 plus fpe easy but i shoot lighter heres a pickView attachment 486141

 

[Stubbers]

You don't need, nor want Tom Hill parts in your Marauder....sigh

All you really need is an ssg (do your own research, plethora of data/info out there using google search terms), and to learn to tune for a bell curve verse a declining shot string while shooting an unregulated gun...As Dairy boy said, you should easily achieve 16~ high power shots, or with a more efficient tune easily 24, and with a great 3-4% extreme spread at most (3% if pellets are weighed/sorted).

The way the Bell Curve works in unregulated guns is that, the hammer/valve balance goes from a valve lock state (not enough hammer strike) at initial fill pressure (3000~ psi + valve return spring), and as the psi lowers each shot, the valve becomes easier to open, which allows more air through which compensates for the lower psi each shot, when balanced ideally, the journey towards the middle of your psi range favors a slight incline in FPS, by now your peak FPS at roughly 2400-2600 psi should be determined by the velocity metering screw, or a transfer path choke, or the porting. Below this peak velocity is where the decline of your bell curve begins, which is generally determined by velocity metering screw/transfer path choke/porting. As pressure continues to fall, it doesn't matter if you add more hammer strike as you'll be at the guns plateau for the remainder of the string until your fps falls outside a reasonable ES %, which is generally 2000-2100 psi for stock marauders, depending on tune.

Hope this helps.

-Matt

 

[3Crows]

Just shot this string with my Gen 1 after being inspired by Stubbers post. These are JSB Exact King 25.4 grain pellets:

880 (3000)
890
894
880
882
876
882 (2600)
----------
870
873
870
869
864
858
858
855 (2300)

After this it trails off with the last shot, #24, at about 38 fpe. I think I could go to a smaller ID TP, maybe back down to .161 (I am at .196 now). That might throttle down the first few shots and give me back a little more on the back side of the curve, maybe even another magazine but the trade off would be a slightly lower average FPE.

At 30 yards, all pellets pass through the same tattered hole, a dime sized group. Nothing super special, AGR FFH, AGR Hybrid tube, AGR cocking assist, bottle brush depinger, slightly modded exhaust valve (drilled out port to .161), barrel port at .161. This muzzle report for this rifle is a snap. The aluminum tube does not ping, the AGR FFH is just a dull thud on the exhaust valve.

 

[Kpac]

Just shot this string with my Gen 1 after being inspired by Stubbers post. These are JSB Exact King 25.4 grain pellets:

880 (3000)
890
894
880
882
876
882 (2600)
----------
870
873
870
869
864
858
858
855 (2300)

After this it trails off with the last shot, #24, at about 38 fpe. I think I could go to a smaller ID TP, maybe back down to .161 (I am at .196 now). That might throttle down the first few shots and give me back a little more on the back side of the curve, maybe even another magazine but the trade off would be a slightly lower average FPE.

At 30 yards, all pellets pass through the same tattered hole, a dime sized group. Nothing super special, AGR FFH, AGR Hybrid tube, AGR cocking assist, bottle brush depinger, slightly modded exhaust valve (drilled out port to .161), barrel port at .161. This muzzle report for this rifle is a snap. The aluminum tube does not ping, the AGR FFH is just a dull thud on the exhaust valve.

Forget stubbies postbrip it apart rebuild a badass airgun lol just messing

 

[3Crows]

Forget stubbies postbrip it apart rebuild a badass airgun lol just messing

Chrono results and a shot string for your rifle with velocity and pellet weight?

There is no way you could get a proper cheek weld with that stock! I have that stock on a Savage .17HMR and it is great for that rifle but it does not have a big air tube and a magazine sticking out of the top. The scope is much, much lower than you have as mounted in the photos on most PBs that are good with that design stock.

The OP asked for a shot string for a relatively stock M-Rod, I guess we went astray some.

 

[Kpac]

Chrono results and a shot string for your rifle with velocity and pellet weight?

There is no way you could get a proper cheek weld with that stock! I have that stock on a Savage .17HMR and it is great for that rifle but it does not have a big air tube and a magazine sticking out of the top. The scope is much, much lower than you have as mounted in the photos on most PBs that are good with that design stock.

The OP asked for a shot string for a relatively stock M-Rod, I guess we went astray some.

I have a lothar walther barrel and i shoot slugs out of mine and that stock is made for an mrod

 

[Kpac]

Chrono results and a shot string for your rifle with velocity and pellet weight?

There is no way you could get a proper cheek weld with that stock! I have that stock on a Savage .17HMR and it is great for that rifle but it does not have a big air tube and a magazine sticking out of the top. The scope is much, much lower than you have as mounted in the photos on most PBs that are good with that design stock.

The OP asked for a shot string for a relatively stock M-Rod, I guess we went astray some.

Here is the proof

 

[Kpac]

Chrono results and a shot string for your rifle with velocity and pellet weight?

There is no way you could get a proper cheek weld with that stock! I have that stock on a Savage .17HMR and it is great for that rifle but it does not have a big air tube and a magazine sticking out of the top. The scope is much, much lower than you have as mounted in the photos on most PBs that are good with that design stock.

The OP asked for a shot string for a relatively stock M-Rod, I guess we went astray some.

I love it when someone is proven wrong and no answer lol

 

[Kpac]

Chrono results and a shot string for your rifle with velocity and pellet weight?

There is no way you could get a proper cheek weld with that stock! I have that stock on a Savage .17HMR and it is great for that rifle but it does not have a big air tube and a magazine sticking out of the top. The scope is much, much lower than you have as mounted in the photos on most PBs that are good with that design stock.

The OP asked for a shot string for a relatively stock M-Rod, I guess we went astray some.

I just dont understand how someone buy a gun and dont do any research about it first i new everything about the mrod before i bought it what kits were offered what kind of stock were sold and that i could irder it with a lothar walther barrel even the extra large bolt handle to the stailess steel carbon fiber shroud i mean everything evenbthe slugs i was gonna use and your still trying to figure out shot strings well good luck hope all works out for you anything else i can help with let me know

 

[3Crows]

I love it when someone is proven wrong and no answer lol

That stock has too low of a comb, it is pretty, but it is too low for a proper cheek weld and eye alignment on that rifle with that scope hiked up high like that. Your posts are so full of horse manure that the entertainment value alone is worth the nonsense endured not to mention the spelling or lack of.

The M-Rod due to the addition of the air tube assembly needs a stock with a high comb, particularly when high rings are stacked on a pic rail to clear the magazine:



OP, I did find this old string, JSB 25.4 pellets, Marauder Gen 2 .25, out of the box:

791 (3000)
792
811
816
840
840
842
832
______
826
801
810
798
775
770
753
738 (1800)

Out of the box it was a little weak and had a lot of hammer bounce evident. I was able to get the velocity up but the Bell curve quickly turned into a a skewed, mostly declining curve. Getting rid of the hammer bounce, first with a home made FFH and now with one from AGR was a pretty big improvement. It is a hammer assembly that integrates the hammer and spring. I like the AGR hammer system though I prefer the JSAR type where the hammer spring is a separate assembly from the free flying hammer.

This is an early iteration of one of my home made FFH systems:



The hammer is not modded but does have a PEEK striker. There is a threaded section, the original hammer adjuster inside the end cap but milled off for setting free flight gap, if that makes sense. The stock hammer always has a preload on the exhaust valve poppet stem. This allows the hammer to bounce back and forth like a jack hammer producing multiple hammer strikes even after the pellet is long gone wasting air and making the b-rrrr-rp sound. A hammer system that does not preload the exhaust valve poppet allows momentum to carry the hammer into the exhaust valve, not spring preload, and thus it virtually eliminates hammer bounce. It only takes a few thousandths to absorb the extra energy and stop the bounce.

You might also Google the B Staley modification, the poor man's regulator . It works but I was not smitten with it in the end.

 

[Kpac]

That stock has too low of a comb, it is pretty, but it is too low for a proper cheek weld and eye alignment on that rifle with that scope hiked up high like that. Your posts are so full of horse manure that the entertainment value alone is worth the nonsense endured not to mention the spelling or lack of.

The M-Rod due to the addition of the air tube assembly needs a stock with a high comb, particularly when high rings are stacked on a pic rail to clear the magazine:



OP, I did find this old string, JSB 25.4 pellets, Marauder Gen 2 .25, out of the box:

791 (3000)
792
811
816
840
840
842
832
______
826
801
810
798
775
770
753
738 (1800)

Out of the box it was a little weak and had a lot of hammer bounce evident. I was able to get the velocity up but the Bell curve quickly turned into a a skewed, mostly declining curve. Getting rid of the hammer bounce, first with a home made FFH and now with one from AGR was a pretty big improvement. It is a hammer assembly that integrates the hammer and spring. I like the AGR hammer system though I prefer the JSAR type where the hammer spring is a separate assembly from the free flying hammer.

This is an early iteration of one of my home made FFH systems:



The hammer is not modded but does have a PEEK striker. There is a threaded section, the original hammer adjuster inside the end cap but milled off for setting free flight gap, if that makes sense. The stock hammer always has a preload on the exhaust valve poppet stem. This allows the hammer to bounce back and forth like a jack hammer producing multiple hammer strikes even after the pellet is long gone wasting air and making the b-rrrr-rp sound. A hammer system that does not preload the exhaust valve poppet allows momentum to carry the hammer into the exhaust valve, not spring preload, and thus it virtually eliminates hammer bounce. It only takes a few thousandths to absorb the extra energy and stop the bounce.

You might also Google the B Staley modification, the poor man's regulator . It works but I was not smitten with it in the end.

Your just upset because you thought you new what your talking about and i proved you wrong just build a propper gun and stop tourching it lol

 

[Kpac]

Your just upset because you thought you new what your talking about and i proved you wrong just build a propper gun and stop tourching it lol

I sorry pal i have opened a love spot for you any help let me know

 

[3Crows]

I sorry pal i have opened a love spot for you any help let me know

Same here. Not enough of us M-Roders left to fuss amongst ourselves .

I was sitting out back shooting targets and along come some invasive collared doves. There are fewer of them now! Then I went back out to pick them up and dispose of them and they were gone. There then appeared a couple of very fat Mississipi Kites with dove feathers hanging out of their beaks. I wonder! The M-Rod is definitely minute of dove .