Marauder My Benjamin Marauder G3 Project

[rayroz]

I think your on to something!

 

[Pumacarl]

I was thinking of making a folding chassis for it. But, maybe I’ll leave it alone LOL.

I keep saying that, then I get bored, or have an idea pop into my head. Then it's off to the races!

 

[Billm]

Had to switch back to lighter pellets, as I am running out of the JTS.

 

[Billm]

Here’s the SD and other info.

 

[Pumacarl]

Had to switch back to lighter pellets, as I am running out of the JTS. View attachment 22782

Bill, you should get one of those Sehkmet(?) guages to check how many psi you are using per shot. I should get one too, I still don't know about long term reliability, so I have been holding off. They're not cheap.

 

[Billm]

Bill, you should get one of those Sehkmet(?) guages to check how many psi you are using per shot. I should get one too, I still don't know about long term reliability, so I have been holding off. They're not cheap.

Yes, I’d like to get one for the FX too.

 

[Pumacarl]

Yes, I’d like to get one for the FX too.

Yeah, that's where I really want one too. My problem with all the guages is how much you have to tighten them sometimes. It's crazy! I swear to God I do not believe how much I had to tighten down the guage on my TalonP. I can't imagine even attempting to tighten down an expensive electronic guage half as much. I'd be freaking out about breaking it.

 

[BenjeneerJohn]

I run those Sekhmet gauges for testing. They are easier to see starting and ending pressure as well as a more consistent regulator set point on repeated testing. I will say the screens can be a little fragile. I have a few that are cracked. They still work fine so it is not that big of a deal.

The Gen 3 uses a o-ring at the bottom of the gauge. They only need to be hand tight to not leak. We have a torque wrench to assemble them in production but the ones I build at my desk are just snugged up.

John

 

[rayroz]

John what or how would you recommend
getting the g 3 gauges to line up with each other ?
Or just leave them alone .
Thanks Ray

 

[BenjeneerJohn]

Ray,
If they are close, you can tighten them up just a little but, if they don't leak, I would leave them alone!

John

 

[rayroz]

I will deal with it , no leaks no problems . Shoots great .

Ray

 

[Billm]

I run those Sekhmet gauges for testing. They are easier to see starting and ending pressure as well as a more consistent regulator set point on repeated testing. I will say the screens can be a little fragile. I have a few that are cracked. They still work fine so it is not that big of a deal.

The Gen 3 uses a o-ring at the bottom of the gauge. They only need to be hand tight to not leak. We have a torque wrench to assemble them in production but the ones I build at my desk are just snugged up.

John

John, what size are the needed gauges? I know I could measure them but

 

[Billm]

One of my grandsons asked to shoot the Marauder last night. So, I put him on the Marauder shooting the Know Your Limits (KYL) rack at 50yds. We had a blast. The smallest gong/paddle is a challenge at 50yds, but he mastered it. Next time we’ll try 75yds. I’m real happy with how it’s shooting. I still feel tempted to try and get the SD more consistent. I think @Pumacarl may be right about it being related to the large plenum and the refresh cycle. All of this has me rethinking what @Franklink was describing about the effects the large Blackwolf plenum has on shooting smaller calibers. I have to admit at the time I thought that was a design flaw and I did not understand the need to displace some of the plenum capacity with pvc to get it to shoot well. It seems there’s more to plenums than I realized

 

[Franklink]

Plenum volume is good, and even required when you're pushing big fpe.

But for modest power, it can be detrimental to consistency.

One of my highest shot count rifles is my Vet Short, probably something in the 40k realm these days. It's lived a couple different lives worth of configurations. One of those changes required the addition of plenum extension so that the tube would be long enough for a stock change. No other change accept adding that plenum (hammer tension, hammer weight, reg pressure, barrel length, projectile, etc all stayed the same). It was interesting to see my ES roughly double with the larger plenum. It went from a typical ES of 8-14 over the fill prior to the plenum addition, up to an ES around 20-25fps after the plenum addition. For what I use that gun for, the larger ES wasn't a deal-breaker and the compromise of the larger ES for the correct length tube was worth it to me.

And sometimes having a bigger plenum so that bigger fpe can be reached is an acceptable compromise. Cuz if the plenum ain't big enough, there is a definite fpe ceiling. Or rather, the plenum is a large fpe limiting factor. 1cc of plenum volume for each fpe desired was a number that floated around for awhile ....(For example, you want an 80fpe gun you need an 80cc plenum.)

 

[Pumacarl]

Plenum volume is good, and even required when you're pushing big fpe.

But for modest power, it can be detrimental to consistency.

One of my highest shot count rifles is my Vet Short, probably something in the 40k realm these days. It's lived a couple different lives worth of configurations. One of those changes required the addition of plenum extension so that the tube would be long enough for a stock change. No other change accept adding that plenum (hammer tension, hammer weight, reg pressure, barrel length, projectile, etc all stayed the same). It was interesting to see my ES roughly double with the larger plenum. It went from a typical ES of 8-14 over the fill prior to the plenum addition, up to an ES around 20-25fps after the plenum addition. For what I use that gun for, the larger ES wasn't a deal-breaker and the compromise of the larger ES for the correct length tube was worth it to me.

And sometimes having a bigger plenum so that bigger fpe can be reached is an acceptable compromise. Cuz if the plenum ain't big enough, there is a definite fpe ceiling. Or rather, the plenum is a large fpe limiting factor. 1cc of plenum volume for each fpe desired was a number that floated around for awhile ....(For example, you want an 80fpe gun you need an 80cc plenum.)

I have, over the years, read many similar accounts. As far as the 1cc/1fpe rule, it's a very general rule for very well ported guns and a good starting point. I have personally experimented with a normally aspirated AAA Paradigm and found 1/2cc per fpe works great. Depends on the gun for sure. This Gen3 does breathe very easily in .25, I don't know what the .22 is like for porting but maybe @BenjeneerJohn will speak to it. I'm interested to hear about it as well.

 

[Billm]

I have, over he years, read many similar accounts. As far as the 1cc/1fpe rule, it's a very general rule for very well ported guns and a good starting point. I have personally experimented with a normally aspirated AAA Paradigm and found 1/2cc per fpe works great. Depends on the gun for sure. This Gen3 does breathe very easily in .25, I don't know what the .22 is like for porting but maybe @BenjeneerJohn will speak to it. I'm interested to hear about it as well.

I used the bore scope to ensure the transfer port was aligned. The only other things that I’ve done are polish the barrel and swap the moderator with one of mine.

 

[BenjeneerJohn]

The gauge threads are G 1/8-28 BSPP.

You probably want to switch to a lower reg pressure if you want to shoot 18g pellets. There is no reason you cannot get a good tune with 18g pellets.

The larger plenum should not cause an issue with getting a good standard deviation with light pellets at a low regulator pressure. We ship them with the reg around 1100 psi. We can keep the standard deviation low and extreme spread low as well. just need to tune the rifle for the projectile.

John

 

[rayroz]

I run my g3 22cal at 1350 psi , SD is 4.6
ES 12 speed av was 883 .
This was a 55 shot test. The total shots on that fill was 140 .
Ray

 

[Billm]

I went out and shot for just a few minutes today. I shot a 5 shot group with JSB 18.1gr pellets and then a 5 shot group with AEA 18.3gr pellets. I disabled the first four shots from the chronograph reading, as the reg had crept up to 2000psi. It seems like the POI has shifted down and to the left 1.5”. It could be there was some wind that I wasn’t seeing. The reg pressure may be too high, but I’m still Impressed. The noticeable part to me was that the point of impact was almost identical. I don’t believe that was the case the other day. Both groups were sub-MOA at 50yds. The SD for the JSB was 1.5fps - that’s the lowest SD I’ve ever seen on any of my airguns. The SD for the AEA 18.3 was 3fps. I then held over 3.5 Mil at 101yds and spun the little turkey spinner for a few shots.

 

[Pumacarl]

That's excellent, especially at those speeds!