Gun Accuracy

[madmogga]

I am looking for so advice and people’s opinion as the my DMR accuracy and if I need to do some more work on it. Ive been working on this new project for a few weeks and have completed all the upgrades, I have not yet taken it to a skirmish but got the opportunity this weekend to shoot it outside for the first time in a friends garden we set a target up at the end of his garden at a measured distance of 25mtr and I was a little disappointed with the results once I dialled in the correct hop I was still getting a spread of around 5 inches (very calm day no wind – shooting using scope and bipod off table top) – considering a DMR should be accurate and should hit targets at range by the time this spread hits 50 -60 -70 mtr ill be way off target. for reference I was shooting Geoffs .36 BB, I am running at 445fps using a Prometheus 455mm 6.03 barrel and maple leaf bucking, ive stabilised the barrel and also shimmed the hop arm (hop unit is a metal ICS until) gun is an ICS CXP MARS DMR

I have a spare Prometheus barrel and hop unit and tried to flat hop it but the results where even worse and my groupings were more like 8-10 inchs with very obvious flyers going either left or right

In your opinions am I expecting too much or should I be looking at better groupings at only 25mtr, also the bucking is new so do I need time for this to break in ?

 

[Samurai]

A normal AEG on 350 fps should hit chest sized target at 50m every time.

On 400 fps, at 60m. Not upgraded DMRs but normal guns, cleaned, and put together properly.

The BBs you are using are fine for this job, so the next thing to look at is the hopup bucking. The maple leaf is good. You will need a soft one for this scenario and it requires the concave nub to work.

I hope you have a non ported cylinder for that long barrel and BB weight and perfect airseal.

I would shim the hopup against the body too. The spring on it is not enough to hold it steady against the gearbox. I usually put a piece of rubber between it's "leg" and the body so when you slide the upper on the lower, it fits snug. This alone can have a huge effect on accuracy.

 

[madmogga]

Thanks Samurai, i am using a soft 60o bucking  but just a standard nub - i have concave nubs so will try that. Yes i have put in a none ported cylinder and my air seal is ok i get around 3-4 fps difference but i would like to try to shim the hop against the  body, not something i have done before and must admit not quite sure what you mean - do you have any images that could help ?

 

[Samurai]

Oh, I wrote between the lower and the hopup, but I wanted to write upper.

Where the double arrow is on the lower left image on this random photo from the internetz.

 

[madmogga]

 that why i got confused, so what you recommend is like the HSA barrel lock down kit https://airlab.parts/pages/hsa-barrel-lockdown-kit-installation-instructions - basically removing the spring and using rubber or o rings as spacers so when i slide in the upper receiver it pushes tight against the hop unit so their is no movement.

ill give that a try.

Also with the maple leaf bucking i have just checked and i am using a flat nub not the concave nub - i like maple leaf bucking but never managed to get the concave nub to work that great i either get no hop or massive over hop - do you have this working ? any tips