M-Rod Double Feeding

Jump to latest Follow Reply
badger5th

badger5th

Member
Jun 25, 2022
964
616
61
Marlborough
I was doing some comprehensive chrony measurements last weekend with a new Caldwell chrony. While running data on my .22 Maurauder I noticed occasional drops in MV from 850 +/- fps to 600 +/- fps AND one less shot in the data string. I suspect I was firing two pellets, can't think of another explanation. The bolt cocking felt "weird" each time this happened and it happened maybe once every 15 shots.

Is this common with the M-rod? Any advise on how to remedy it? Thanks.
 
A double feed could only happen if you manually work the bolt twice. In that case, take more care not to do that. The bolt needs to deliberately move to the rear and then deliberately forward until it is locked in the down position. There’s no room to move the bolt backwards after you’ve begun moving it forwards. Just always go backwards all the way… then forwards all the way.
It is also possible that you have some friction going on with the striker, or that the screw in the bolt or hammer is loose causing some interference. A quick disassembly and cleaning, lube and correct reassembly should solve the issue.
•Edit for spelling.
 
Last edited:
  • Like
Reactions: badger5th
Upvote 0
I've had it happen that the bolt is pulled back far enough to allow the next pellet to drop in front of the probe, but not far enough back to actually cock it. In this case, the bolt slides forward under the hammer's spring tension. When it's cocked, the bolt should need to be shoved forward. When it doesn't fully cock, the movement of the bolt forward will seat a pellet in the barrel, then you give the bolt a hard pull back to actually cock it, but now you have a second pellet in front of the probe. When you finally slide that second attempt home, you're now double fed.
When this happens, I pull the bolt back so it actually cocks, then remove the magazine and slide the bolt forward. This way, the second pellet will not get loaded. But you need to be aware in order for this to work.
Edited to add: Finding a tune that does not max out the hammer spring should also reduce cocking effort, which should also reduce the occurrence of this type of double-feed.
 
Upvote 0
Possible , for what ever reason, that the pellet is cocking and not feeding true. Possibly distorting skirt.
On the double feed, I try , religiously, to NOT cock and load the rifle until ready to shoot. I can't count the # of times I've chambered a pellet, got distracted, come back and cocked her again!
 
  • Like
Reactions: Glem.Chally and rcarlisle
Upvote 0
pnwairgunner said:
A double feed could only happen if you manually work the bolt twice. In that case, take more care not to do that. The bolt needs to deliberately move to the rear and then deliberately forward until it is locked in the down position. There’s no room to move the bolt backwards after you’ve begun moving it forwards. Just always go backwards all the way… then forwards all the way.
It is also possible that you have some friction going on with the striker, or that the screw in the bolt or hammer is loose causing some interference. A quick disassembly and cleaning, lube and correct reassembly should solve the issue.
•Edit for spelling.
Click to expand...
Thanks, Thinking about it the cocking action doesn't feel right when this happens. It feels like the hammer is not being set now that I think about it. Close the bolt, chamber a pellet, pull the trigger, nothing.. Work the bolt a second time, pulling it back with more authority, feel the hammer set, close bolt chambering the second pellet. Then Both pellets go out when I shoot.

Funny thing is the fpe muzzle energy is the same with two pellets at 600 fps vs one at 850fps. (24 fpe each case).
 
Upvote 0
badger5th said:
Thanks, Thinking about it the cocking action doesn't feel right when this happens. It feels like the hammer is not being set now that I think about it. Close the bolt, chamber a pellet, pull the trigger, nothing.. Work the bolt a second time, pulling it back with more authority, feel the hammer set, close bolt chambering the second pellet. Then Both pellets go out when I shoot.

Funny thing is the fpe muzzle energy is the same with two pellets at 600 fps vs one at 850fps. (24 fpe each case).
Click to expand...
Something you can try to help alleviate that would be to turn the hammer spring adjustment counter-clockwise a couple turns to reduce the amount of force you need to get the hammer to lock in the rearward position. If it is turned in to increase power it can make it hard to operate the bolt fully.
I’d suggest backing the adjustment screw out ALL the way and work your way forward a single turn at a time with it while chronographing your speed at each turn in on the screw. Something to remember…..Ultimate power will never give you ultimate accuracy with the Marauders. Start comparing your group sizes from about 800fps up to 900ish and find the speed that gives you what you are looking for in accuracy. A lot of people that are new to pcp airguns think that they need to crank the power up to the max to get the most from their airgun and that is never the case. It’s just wasting air, making the bolt harder to operate, and is detrimental to accuracy.
Sorry for the rambling here but good luck on your tuning!
*spelling edit
 
Last edited:
Upvote 0
pnwairgunner said:
Something you can try to help alleviate that would be to turn the hammer spring adjustment counter-clockwise a couple turns to reduce the amount of force you need to get the hammer to lock in the rearward position. If it is turned in to increase power it can make it hard to operate the bolt fully.
I’d suggest backing the adjustment screw out ALL the way and work your way forward a single turn at a time with it while chronographing your speed at each turn in on the screw. Something to remember…..Ultimate power will never give you ultimate accuracy with the Marauders. Start comparing your group sizes from about 800fps up to 900ish and find the speed that gives you what you are looking for in accuracy. A lot of people think that they need to crank the power up to the max to get the most from their airgun and that is never the case. It’s just wasting air, making the bolt harder to operate, and is detrimental to accuracy.
Sorry for the rambling here but good luck on your tuning!
Click to expand...
Thanks for the adjustment tip. If there is a decent YouTube video on how to do these type of adjustments on an M-Rod I'd be very grateful for a link. Serious PB shooter and handloader for 40 years but I am fairly new to serious air gunning and one month old brand new to PCP's. In the past 5 months I've really fallen down the airgun rabbit hole.

I am content with my current power level (850 fps with average weight pellets). Won't object to slightly less power if that will make the bolt smoother/easier. No plans to shoot critters, happy enough with great accuracy at 50 yards or so.
 
Upvote 0
I've seen this a couple times where the hammer will bind towards the end of the cocking stroke. Removed hammer, inspected tube and hammer and could see no reason for this binding, replaced with a different hammer and the binding went away in both cases. Before replacing the hammer on one I put a little graphite in the tube for a dry lube on the hammer and it also helped tremendously. I forgot to mark one of these hammers and put it in another gun and it then had the same bind, put that one in the junk drawer.
 
  • Like
Reactions: badger5th
Upvote 0
jphef said:
I've seen this a couple times where the hammer will bind towards the end of the cocking stroke. Removed hammer, inspected tube and hammer and could see no reason for this binding, replaced with a different hammer and the binding went away in both cases. Before replacing the hammer on one I put a little graphite in the tube for a dry lube on the hammer and it also helped tremendously. I forgot to mark one of these hammers and put it in another gun and it then had the same bind, put that one in the junk drawer.
Click to expand...
Yes, binding is a good way to describe it. The bolt does not seem to come all the way back when I have the double feed issue. I'm going to shoot another few hundred pellets through it in the event that it may be a break-in issue(?) If it still happens I'm going start learning about the guts of these things hands on. Any good M-Rod "manuals" out there, even a PDF online?
 
Upvote 0
pnwairgunner said:
Definitely go to the marauderairrifle.com forum and do research there. I dont think it’s very active anymore but it is a wealth of information for you there.
Click to expand...
Just went over there. Site is still up but the forums no longer seem to be active. I did find a decent PDF file for M-rod tuning. Will study a bit and try some adjustments.
 
Upvote 0
badger5th said:
Just went over there. Site is still up but the forums no longer seem to be active. I did find a decent PDF file for M-rod tuning. Will study a bit and try some adjustments.
Click to expand...
Oh man! That stinks! If you need any help feel free to PM me on here and I’ll get back to you as quick as possible. There are also some videos on YouTube that go through tuning the marauder. (Most of them are probably high power tunes.)
 
  • Like
Reactions: badger5th
Upvote 0
pnwairgunner said:
Oh man! That stinks! If you need any help feel free to PM me on here and I’ll get back to you as quick as possible. There are also some videos on YouTube that go through tuning the marauder. (Most of them are probably high power tunes.)
Click to expand...
Very grateful for the offer. I did find a tuning guide PDF on the website even though the forums are down. I am also blessed to live in the next town over from New England Airguns who have thorough service facilities.
 
  • Like
Reactions: pnwairgunner
Upvote 0
You must log in or register to reply here.
Top Bottom
Back
Home
Forums
Resources
Menu