RAW Microhunter Airstripper tuning

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When I first saw images of the Micro Hunter it simply looked sweet, particularly the esthetic of the squared off bottle. Can’t imagine that it wouldn’t group at 10 meters. As per the situation described by @jps2486. I applaud that you gents are so patient and diligent in trying to suss out the Issues. That said, tomorrow after work am going to send a whole magazine at 10 meters out of my Pathfinder to see what may develop.
 
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So far my Pathfinder (ctshooter's old gun) totally puts the Micro Hunter to shame in the accuracy department. Of course Sean put a lot of work into to that gun before he decided to sell it.

The only place where the Micro Hunter truly beats the Pathfinder (actually blows it out of the water) is that sublime trigger. So smooth, crisp and precise, and adjustable down as low (or even lower) as one would ever want in a hunting gun.

The Pathfinder definitely didn't like Hades pellets, but give it Monster Re-Designs, Benjamin 10.5's or Baracuda Match 10.65's and it is real happy. And it shot Crosman Ultra Magnum 10.5's pretty much like the best groups I can get out of my Micro Hunter (i.e.: Not real good).

IMG_3565.JPG
 
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jps2486 said:
This is a new gun and barely 3 weeks old. Unfortunately, I didn't buy it from Martin so if I send it to him, it costs me $$. I'm dealing with RAW (Air Force) currently on the problem and I'm hoping they correct it under warranty.
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Can AF just send you another barrel.? or swap you out.? It still could be the barrel even with all the prep. At least then you could eliminate barrel as being problem if they would do that. Also I just had Sightron fix one of my SIII's as I new something was off on a very accurate airgun. It was the parallax adjustment,it was off & not functioning correctly. Just throwing that one out there as I know your a seasoned vet in the air game (y)
 
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I feel like you have the experience to have eliminated this already but on a couple of occasions very very light clipping with muzzle devices - barely enough to even leave a mark - have turned out to be the source of extremely aggravating situations similar to yours. If you can't remove the airstripper, maybe try sorting a handful of pellets and see if it's happening more often with the largest diameter pellets.
 
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TMH said:
So far my Pathfinder (ctshooter's old gun) totally puts the Micro Hunter to shame in the accuracy department. Of course Sean put a lot of work into to that gun before he decided to sell it.

The only place where the Micro Hunter truly beats the Pathfinder (actually blows it out of the water) is that sublime trigger. So smooth, crisp and precise, and adjustable down as low (or even lower) as one would ever want in a hunting gun.

The Pathfinder definitely didn't like Hades pellets, but give it Monster Re-Designs, Benjamin 10.5's or Baracuda Match 10.65's and it is real happy. And it shot Crosman Ultra Magnum 10.5's pretty much like the best groups I can get out of my Micro Hunter (i.e.: Not real good).

View attachment 498527
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Glad you're still liking the Pathfinder and it's been working great for you.

I, just the week, acquired a 177 Micro Hunter and have been messing with it for a few days. As other's have mentioned - the trigger is amazing. I've only had the chance for 10yards but so far the Benjiman 10.5gr have been doing nicely. Trying out the H&N Barracuda Match 10.65gr as well - these seem to have a few fliers.

I don't have much to report here on performance. But, I would like to detune it to shoot the 10gr pellets around 700 fps. I see written on the reg 145 and around 150 on the gauge is where is seems to drop off fps. But the hammer spring adjustment is very limited and I can only move the speeds in the 765 - 800 fps range.

Are there any tuning videos or other tuning information ot there?
 
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ctshooter said:
I don't have much to report here on performance. But, I would like to detune it to shoot the 10gr pellets around 700 fps. I see written on the reg 145 and around 150 on the gauge is where is seems to drop off fps. But the hammer spring adjustment is very limited and I can only move the speeds in the 765 - 800 fps range.

Are there any tuning videos or other tuning information ot there?
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I haven't tried tuning my HM1000 down to any significant degree. You are attempting a sub 12 fpe tune, and some rifles need a different hammer, spring, and/or regulator to achieve a properly balanced tune at that level, but I don't know about the RAW. As an experiment, turn your HST down, then shoot the bottle pressure down below the set point, and see where your velocity is when you get down to 100 or a bit below. That might tell you whether the existing assembly is compatible with the tune you want.
 
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Jaxjax said:
Can AF just send you another barrel.? or swap you out.? It still could be the barrel even with all the prep. At least then you could eliminate barrel as being problem if they would do that. Also I just had Sightron fix one of my SIII's as I new something was off on a very accurate airgun. It was the parallax adjustment,it was off & not functioning correctly. Just throwing that one out there as I know your a seasoned vet in the air game (y)
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I think this gun was not assembled properly. Running the hammer spring nut from one end to the other yields no change in velocity.
 
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elh0102 said:
I haven't tried tuning my HM1000 down to any significant degree. You are attempting a sub 12 fpe tune, and some rifles need a different hammer, spring, and/or regulator to achieve a properly balanced tune at that level, but I don't know about the RAW. As an experiment, turn your HST down, then shoot the bottle pressure down below the set point, and see where your velocity is when you get down to 100 or a bit below. That might tell you whether the existing assembly is compatible with the tune you want.
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Thanks for the reply. From what I have read so far from various places you are correct saying that the tune is factory set within a certain range with a certain spring and about two turns worth of play on the hammer spring. Honestly for right now I'm happy with the factory tune so I'm gonna break in the Micro as is and maybe tinker down the road.

FYI - for anyone curious about moderator testing I put an Impulse Air IA-1200 on mine with one extra baffle and it is super quiet.
 
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Here are the most recent groups which I am having reviewed by RAW. All are Monster Re-Design 13.43's at 25 yards, no wind but heavy air (on the order of 60 F and 90% RH). Pellet velocity was almost 720 fps (as recommended by RAW). Different groups are testing different air stripper settings. Some groups have the same AS setting, if the first group shot showed promise. Gun always refilled as it approached 150 bar on the gauge. Shot off Caldwell stable table, Accu-Tac bipod and rear bean bag. All groups are 10 shots.

I am comparing these groups and considering them sub-par based on other .177 cal guns (including the Pathfinder), and RAW's specification that the Micro Hunter produces "10 meter accuracy in a compact hunting rifle". Many of the group sizes might be acceptable to to me - if not for the flyers!

Note one bad trigger pull I called on myself in the last group - trigger is so light it broke before I was fully ready.

IMG_3693B.jpg
 
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TMH said:
Here are the most recent groups which I am having reviewed by RAW. All are Monster Re-Design 13.43's at 25 yards, no wind but heavy air (on the order of 60 F and 90% RH). Pellet velocity was almost 720 fps (as recommended by RAW). Different groups are testing different air stripper settings. Some groups have the same AS setting, if the first group shot showed promise. Gun always refilled as it approached 150 bar on the gauge. Shot off Caldwell stable table, Accu-Tac bipod and rear bean bag. All groups are 10 shots.

I am comparing these groups and considering them sub-par based on other .177 cal guns (including the Pathfinder), and RAW's specification that the Micro Hunter produces "10 meter accuracy in a compact hunting rifle". Many of the group sizes might be acceptable to to me - if not for the flyers!

Note one bad trigger pull I called on myself in the last group - trigger is so light it broke before I was fully ready.
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When you refer to RAW, do you mean Martin, or the Texas folks. Assuming favorable variables, those are terrible groups for a RAW at 25 yards. I just shot my .22 HM1000 in the yard at 25 yards. Sitting on my deck step and using only my knees and a shooting stick, my groups were one-hole, which is typical for me and that rifle at that distance.
 
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elh0102 said:
When you refer to RAW, do you mean Martin, or the Texas folks. Assuming favorable variables, those are terrible groups for a RAW at 25 yards. I just shot my .22 HM1000 in the yard at 25 yards. Sitting on my deck step and using only my knees and a shooting stick, my groups were one-hole, which is typical for me and that rifle at that distance.
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Texas folk. Rapidairworx.com. From their Outlet store.

I buy from Martin too, but all I know about a storefront for him is Airguns-USA.com.
 
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TMH said:
Texas folk. Rapidairworx.com. From their Outlet store.

I buy from Martin too, but all I know about a storefront for him is Airguns-USA.com.
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Yes, that's his site. You can call or email and order directly from him. I talked to him today, great guy. I have no experience with the Texas folks. I'm sure they are fine people, but based on my history with Martin, I'll never buy a RAW any other way. At one time, I thought that all RAW rifles were assembled and shipped by him in TN, but I'm not sure of their process currently. But I know this, if I talk to him and he tells me something, I can absolutely depend on it. He's never let me down.
 
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For you guys having some issues, I have found that finding the proper size pellets for my barrels almost always resolves my issues. Just because you have tried different pellet weights, doesn't mean that you have yet tried different pellet head sizes. In .177 I recommend that you pick up some JSB Exact 8.44gr in 4.50, 4.51 and 4.52 head sizes, and try them. My TM1000 will go from 1/2 inch groups at 55 yards with small head size pellets, to .220" groups with 4.52 pellets. You can also try different brands of the same weight, because they are often different sizes. Your aim is to just find the best head size for your gun. A PelletGage and a chronograph are invaluable tuning tools IMO.
I did a lot of testing on the Micro at 25yds and beyond and I have seen some larger groups if the air stripper is screwed all the way in. Usually I end up with it about 6 turns out, or I even remove it. The proper setting just depends on the pellets you are using.
Also, I recommend that you try an Impulse Air moderator if you have the means. It is the ONLY moderator I have tried that uses cones internally, and it has time and again reduced my group sizes when other moderators of the same weight will not.

@BrazosbyNemo how are your Micro group sizes at 25yds?
 
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ctshooter said:
Glad you're still liking the Pathfinder and it's been working great for you.

I, just the week, acquired a 177 Micro Hunter and have been messing with it for a few days. As other's have mentioned - the trigger is amazing. I've only had the chance for 10yards but so far the Benjiman 10.5gr have been doing nicely. Trying out the H&N Barracuda Match 10.65gr as well - these seem to have a few fliers.

I don't have much to report here on performance. But, I would like to detune it to shoot the 10gr pellets around 700 fps. I see written on the reg 145 and around 150 on the gauge is where is seems to drop off fps. But the hammer spring adjustment is very limited and I can only move the speeds in the 765 - 800 fps range.

Are there any tuning videos or other tuning information ot there?
Click to expand...
Turning the hammer spring all the way in and out with little to no change in velocity indicates the hammer is over sprung and the velocity is set by the regulator. You should remove the action from the chassis, back out the Hammer Spring adjuster and look for a washer under the spring. If there is one, remove it and reassemble then test again. With proper springing, you should be able to adjust the velocity 20-30fps or so. I've turned the Micro down to 12fpe with 8.44gr pellets, but that requires the regulator to be turned down to about 110bar.
 
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TMH said:
I agree wholeheartedly with all positive comments regarding Martin, and his intimate knowledge of RAW guns. And his expert work.

I do believe that RAW guns, at least ~8 months ago, were being completely fabricated at their Ft. Worth, TX facility. At least based on the AEAC Factory Tour video I watched.

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All RAW airguns are fabricated, assembled and tested in Fort Worth TX.
 
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TMH said:
Here are the most recent groups which I am having reviewed by RAW. All are Monster Re-Design 13.43's at 25 yards, no wind but heavy air (on the order of 60 F and 90% RH). Pellet velocity was almost 720 fps (as recommended by RAW). Different groups are testing different air stripper settings. Some groups have the same AS setting, if the first group shot showed promise. Gun always refilled as it approached 150 bar on the gauge. Shot off Caldwell stable table, Accu-Tac bipod and rear bean bag. All groups are 10 shots.

I am comparing these groups and considering them sub-par based on other .177 cal guns (including the Pathfinder), and RAW's specification that the Micro Hunter produces "10 meter accuracy in a compact hunting rifle". Many of the group sizes might be acceptable to to me - if not for the flyers!

Note one bad trigger pull I called on myself in the last group - trigger is so light it broke before I was fully ready.

View attachment 498710
Click to expand...
My groups are a lot better than that. I don’t have any targets laying around that I have shot woth the Micro. I would say nickel sized groups at 30 yards with JSB 8.44 or H&N FTT. Before it was turned down to 12fpe it did the same with JSB/AA 10.3 and almost as good with Crosman Premier Heavies. Norma 8.4 & 9.1 (I think the are 9.1) shot a bigger group, about the size of a quarter until I stuck the RYU moderator on it and the Norma’s went crazy. All the groups I am talking about are 1 magazine worth of shooting. Maybe not a full magazine everyrime as once you have a ragged hole you tend to start another. I have not done a proper job of phoning in on making the rifle more accurate (pellet testing, air stripper adjustment, etc). That’s my project for the spring. I really like the rifle. It’s a 5lb rifle. I don’t expect it to be a full blown match rifle as that was not what it is designed for though It does share a lot of the RAW pedigree.

I am editing this as it occurred to me my shooting has not been off the bench. I shoot in the seated FT position like I would in a FT match. I could probably do better off a bench.
 
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