Marauder Project – .22 Tuning (part 1)   3 comments

Greetings all,

I received my new ProChrony last week. I did a bit of tuning of the .177 Marauder for a little on Thursday. For the .177, all I did was make 1/2 or whole turns to the hammer spring and hammer stroke. I did not adjust the metering screw. I believe I now have the .177 at 19.5/20 fpe.

Friday evening I started trying to get the most out of the .22 but was having issues. The main reason is because I was not documenting what I was doing. I was getting a bit frustrated because the fps was there (850-900 for Kodiaks) but only for about 9-10 shots. This was not going to work for how I am planning to hunt around the farm.

This morning I got up and was determined to have the .22 in decent shape. After reviewing the A-Team document, I gathered up all my gear and headed out to the bench. After getting everything in order, I began my testing.

The Workbench

Workbench 2

I began with the following settings. I realized I misread the A-Team’s “how-to” later, but for now… here is where I started.

    HTS – Hammer Tension Spring; Starting position is clockwise (CW) until I heard click.
    HSA – Hammer stroke adjustment; Starting position is counter-clockwise (CCW) until stops.
    MS – Metering Screw; I turned metering screw all the way in until it stopped. I then turned back out two rotations.

I start by decreasing the HSA by one turn. Here is the data.
Start – 2800 psi; CP 14.3;
30 shot string, H – 930; L – 854; Av – 920; Es – 76; Sd – 24

    Sting:
    928
    922
    924
    930
    926
    926
    930
    924
    925
    922
    920
    921
    917
    912
    910
    907
    905
    902
    900
    891
    883
    886
    887
    878
    876
    873
    870
    862
    858
    854

At this point I refilled to 2800 PSI and re-read the tuning document. I found that I misread the document and turned the HTS counter-clockwise until it stopped (about 8 turns). I then turned the HTS clockwise four turns.

Here is the output of the cronying and tuning:
787;
+1 HTS turn CW.
err
831
832
+1 HTS turn CW.
890
+1 HTS turn CW.
913
897

PSI @ 2600; Refill to 2800;
err
872
902
883
+1 HTS turn CW.
900
905
-1/2 HSA turn CCW
888
911
913
912
Current pressure… ~2650 – 2700 psi
901
922
-1/2 HSA turn CCW
err
894
905
907
915
910
921
905
915
Current pressure… ~2400 psi

My laptop battery was getting too low to continue using. So I was forced to continue manually… oh the horror. 🙂

Continuing…
=============Refill to ~2800 psi=====================
854
+1 HTS turn CW.
864
868
869
876
877
885
889
886
892
893
896
Current pressure… ~2600 psi
898
900
900
-1/2 HTS turn.
891
887
886
894
894
894
900
899
900
900
Current pressure… ~2400 psi
899
898
899
897
897
896
891
887
Current pressure… ~2050 – 2100 psi
885
883
879
880
874
874
872
861
Current pressure… ~1950 – 2000 psi

====================Refill to ~2800 psi====================
The numbers seem decent (not great) with Crosman Premiers. So I decided to switch from CP (14.3) to JSB Exact 18 grain pellets.
767
772
783
786
772
777
774
784
791
790
Current… ~2600 psi
+1/2 turn of MS
err
804
805
+1/2 turn of MS
812
811
817
827
838
830
Current… ~2400 psi
830
844
847
852
846
851
854
855
854
861
862
Current… ~2100 psi
858
859
863
859
854
Current… ~2000 psi
856
849
838
846
843
Current… 1800 psi
824
829
829

According to CharGun Pro, I am at the 30 fpe mark. This is where I want to be with the .22 Marauder.

Continuing on…
=======================Refill to 2800 psi==================
781
785
778
776
err
778
791
774
793
797
806
Current… 2600 psi
819
807
817
824
834
Current… ~2500 psi
822
825
835
838
841
855
849
855
854
851
Current… ~2100 psi
859
859
865
Err
859
857
861
853
851
845
844
841
833
Current… ~1800 psi
833
829
823
814
Current… ~1700 psi

It is clear the valve is has a partial lock from 2800 to approximately 2500 psi. I stayed at 2500 psi from henceforth.

=============Refill to ~2500 psi=================
+1/2 MS
836
831
833
839
852
854
842
Current… ~2400 psi
Switched to Beeman Kodiaks
791
784
792
795
Current… ~2200 psi
806
Swapped to Barracuda Match pellets
806
807
812
821
809
823
812
Err
806
Err
802
Current… ~1900 psi
801
801
Err
789
Current… ~1800 psi

At this point, the rifle seems consistent and gives a nice shot string. However, it can still using some further tuning. What exactly I am not sure. Perhaps in the next few days I will go crony the Barracuda pellets and see how many shots I am getting. I would like 25-30 good shots.

Afterward I will need to determine what is the best shooting pellet. I did get a nice four shot group with the Beeman Kodiak pellets.

Until next time.. same bat time, same bat channel.

Blessings,
Jeff

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Posted April 17, 2010 by avv604 in Marauder

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3 responses to “Marauder Project – .22 Tuning (part 1)

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  1. i just bought a marauder .22 on 4-28-11 and was factory set at 2500 psi , i was told from prymidair that 14.3 grs velcocity 830 fps and if i decided to tune up that it will not group?? i would like to get in the high 900’s …what do u think

  2. Greetings Irfan,

    It sounds like Pyramid has given some poor advice. My .22 loves JSBs and they are running at over 900fps. I would just see which pellet the rifle likes and then tune from there.

    Also, disregard most advice since your rifle will be different than other M-rods.

    Hope you enjoy!

    -Jeff

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