G2 Mrod group. Is this good?

[tpw037]

Recently purchased a G2 Mrod. I've tuned the gun first, using Dave Hisownself method, I think called the BLT. It's a 6-6-5 tune. Then I tried the A- team method. I can't seem to get my velocity past 860. I'm shooting JSB king 25.39. I've tried various starting psi and my groups are pretty consistent but I'm not that happy. All the info is on the card, psi start, avg vel, spread etc., but long and short, 8 shot groups, 30yds and this is my best. The last card is using H&N baracuda 30.86g and it's about the same. Is this the best an M rod can do, or is it just me?

Any words of wisdom from the community?

 

[Airgunmann]

Do u have the valve port all the way open the striker backed up all the against the Hammer and hammer spring tighten up most of the way or did u put orings behind the valve for b- Staley mod ?

 

[bearair]

Tune looks pretty good to me. A 1/2 inch group is pretty good even at 30 yards. 23 fps spread is excellent in a un regged gun. I own mostly regged guns so the power level and tuning I can't say too much but perhaps tightening up the group might be something pretty simple. I know spending more money is the last thing you wanna do but... I suggest getting a hill barrel band. Some guys like the free floating ish barrel but I personally have had better luck using that barrel band which holds the barrel very solid. Also a little divers grease on the front shroud spacers oring can make a difference too. Hill also offers .160 transfer ports too. Might be worth looking at hill airgun parts website. Good luck.

 

[Airgunmann]

Tune looks pretty good to me. A 1/2 inch group is pretty good even at 30 yards. 23 fps spread is excellent in a un regged gun. I own mostly regged guns so the power level and tuning I can't say too much but perhaps tightening up the group might be something pretty simple. I know spending more money is the last thing you wanna do but... I suggest getting a hill barrel band. Some guys like the free floating ish barrel but I personally have had better luck using that barrel band which holds the barrel very solid. Also a little divers grease on the front shroud spacers oring can make a difference too. Hill also offers .160 transfer ports too. Might be worth looking at hill airgun parts website. Good luck.

I agree with you the tune isn't bad at all for mrod my old one I could do 16 shots for about a 20 fps spread on a fill I thought it was a tad faster though but I I forgot I was modded out as far as valve, transfer port and longer hammer throw 860 isn't bad for 25gr

 

[Airgun-Revisions]

Tune looks pretty good to me. A 1/2 inch group is pretty good even at 30 yards. 23 fps spread is excellent in a un regged gun. I own mostly regged guns so the power level and tuning I can't say too much but perhaps tightening up the group might be something pretty simple. I know spending more money is the last thing you wanna do but... I suggest getting a hill barrel band. Some guys like the free floating ish barrel but I personally have had better luck using that barrel band which holds the barrel very solid. Also a little divers grease on the front shroud spacers oring can make a difference too. Hill also offers .160 transfer ports too. Might be worth looking at hill airgun parts website. Good luck.

The valve and barrel are .140. The .160 TP will create turbulence and render it ineffective.

 

[Airgun-Revisions]

You are trying to overpower the gun making your groups open up especially at the low end where the valve is dwelling. What your not looking at is what velocity the barrel is most accurate at. In this case the 25.3 like 840 best in Marauders. Don’t let speed hinder your goal of accuracy. Speed means squat if it’s not. Most don’t see the difference in 20fps. More of an ego thing. But most of all have a good plan together before you just throw parts in it thinkin something should work.

 

[tpw037]

Thanks for the input. I will try to back off the HS to bring the velocity down some. My transfer port is wide open so I'll try each of those adjustments to see which may be better for me. I though it was crazy that shots 9-16 had an even lower spread but the groups were so much worse. It looks like the velocity was higher though. I'm going to aim for 840fps like you recommend. Then the next part will be finding out what pressure to pump to and how many good shot I can get. Thanks again for the replies.

 

[bearair]

Thanks Rich I wasn't aware of said turbulence.

 

[Airgun-Revisions]

Thanks Rich I wasn't aware of said turbulence.

No worries. There are three parts to the entire port. All three need to match for proper flow.

 

[BZapp7]

I recall getting .75 inch-ish 8 shot groups with my . 25 mrod at 50 yds. I don't think you're too far off the norm as far as accuracy goes. I believe I had similar thoughts about mine... then eventually bought an fx royale

 

[tpw037]

I thank everyone for the feedback. I kept tinkering and it just wasn't where I wanted it to be. 1/2" group @ 30yd is OK I guess. I'm coming from a custom AR-10T that shot less than that @ 100yd. I know conventional powder vs. an airgun is a big difference but I was hoping for better so I did something drastic. I got an fx impact m3 700mm in .30cal. Now I'm stacking holes @ 30yds out of the box. I was blown away with the performance, but I guess I should be with a 2k+ rifle. Anyhow, I guess I don't have much need for the marauder anymore. I'm looking to offload it and wanted to say that here on this post first if there's any interest since you all helped me.

 

[rodbuilder]

Are you shooting with wind flags? BIG variable there - and takes time to learn to read the wind. My .25 marauder is one hole, < .25” IF I pay attention to wind flags! Minute of squirrel without flags.

 

[bearair]

Enjoy the Impact.