Why does my MM-B28 sound like its going to explode?

[jberenyi]

The sun does shine once in a while.

Problem solved. Upon further inspection of the action where the pellet seats I noticed that on this model rifle the face of the action is NOT perpendicular to the bore of the barrel. Therefore the chamfer by default will always be heavier on top then on the bottom of the bore if you chamfer true to the axis of the bore. The factory just didn't go deep enough with the tool. I had a chamfer tool from work and went a little deeper (.010-.012)following the axis of the bore and now all is well. I was sweating pellets there for a second. I didn't realize this was the case until I looked at my B26 face which IS perpendicular to the bore allowing for a uniform chamfer all the way around.

[tjk]

Why bother champhering it at all?  You really shouldn't need to, and by placeing the pellet in correctly, all you may need to do is seat the pellets with a pel-seat or round end swizzle stick,...especially if the skirts fit real snug. But take heart,...I had the same experience when I got my 34 Diana and didn't realized the breech block was angled to the reciever. No Big deal so don't sweat it. Now,....Just shoot the living hell out of that rifle and show NO Mercy!!!!!!! Don't mistreat it or slam the barrel real hard when  cocking and returning to lock up,...just shoot it, shoot it,...and then shoot it some more. I promise this rifle will wear you out be for you can wear it out!!!!!! LOL's, You're really gonna love this rifle once you tame it some,....I guarantee it!!!! tjk

[jberenyi]

tjk - 6/10/2009 11:03 AM Why bother champhering it at all? You really shouldn't need to, and by placeing the pellet in correctly, all you may need to do is seat the pellets with a pel-seat or round end swizzle stick,...especially if the skirts fit real snug. But take heart,...I had the same experience when I got my 34 Diana and didn't realized the breech block was angled to the reciever. No Big deal so don't sweat it. Now,....Just shoot the living hell out of that rifle and show NO Mercy!!!!!!! Don't mistreat it or slam the barrel real hard when cocking and returning to lock up,...just shoot it, shoot it,...and then shoot it some more. I promise this rifle will wear you out be for you can wear it out!!!!!! LOL's, You're really gonna love this rifle once you tame it some,....I guarantee it!!!! tjk

I plan on shooting the hell out of this rifle for sure. I just love it with the chopped/crowned barrel and muzzle break. Since having that done the weight on this thing is awesome. It weighs the same as my MM-B26. Off hand before break-in I'm already shooting 3/4" groups! This thing will be a tack driver as break-in proceeds

[jberenyi]

The black cloud has moved in again! Now the rifle will not cock past 90 degrees to set up the safety and spring piston. As I cock and approach 90 degrees the barrel comes to a hard stop and will not go any further. What the heck is causing this now? I swear if I have to send this rifle back to Mike again then it will be up for sale. This is bull crap.

[tjk]

Just out of curiousity,...what pellets have you been shooting with the B-28? Too light or too heavy will eventually snap a spring with continued use. Sounds like your spring has snapped, and it has inter twinned within itself. Hence catching the rear guide and jambing it. Have you ever dry fired this rifle?!? More than a few times maybe? Not trying to be condescending to you or your intelligence,...but there has never been a springer shooter in history that hasn't inadvertantly dry fired his or her rifles. Is the spring factory or after-market?!? Which ever the case,...Mike stands behind his rifles and the work he does on them. I hate that you've had an unpleasant experience with your B-28. tjk
PS. Just a theory here, but maybe altering the barrel (chopping it) may have had something to do with this,...I don't know,...change in harmonics or something,...too little pellet resistance travelling down the barrel simulating a dry fire?!?!?. So many variables to consider here.

[jberenyi]

tjk - 6/19/2009 4:50 AM Just out of curiousity,...what pellets have you been shooting with the B-28? Too light or too heavy will eventually snap a spring with continued use. Sounds like your spring has snapped, and it has inter twinned within itself. Hence catching the rear guide and jambing it. Have you ever dry fired this rifle?!? More than a few times maybe? Not trying to be condescending to you or your intelligence,...but there has never been a springer shooter in history that hasn't inadvertantly dry fired his or her rifles. Is the spring factory or after-market?!? Which ever the case,...Mike stands behind his rifles and the work he does on them. I hate that you've had an unpleasant experience with your B-28. tjk PS. Just a theory here, but maybe altering the barrel (chopping it) may have had something to do with this,...I don't know,...change in harmonics or something,...too little pellet resistance travelling down the barrel simulating a dry fire?!?!?. So many variables to consider here.

I've been shooting RWS Superdomes since I bought it and it has never been dry fired either. It was working fine just a few days ago. I finally got some new Hawke scopes to install and now this. The last time Mike worked on this he put a JM spring and seal in it. I even took great care to cock slowly like Mike said. I can't believe that the last shot I took with this thing was the defining moement for it before retiring it to the house. This is bizzare. I am so bummed because vacation is coming soon and now my son will not have a rifle to shoot. This will be the last Chinese rifle I will ever buy if it has to be sent back again.

[jberenyi]

Well it looks like Mike wants just the action now so he can replace it completely. Therefore, this will be my LAST Chinese air rifle. All I have to do now is just paint the stock bright yellow.

[man00]

jberenyi - 6/19/2009  6:08 AM

Well it looks like Mike wants just the action now so he can replace it completely.  Therefore, this will be my LAST Chinese air rifle.  All I have to do now is just paint the stock bright yellow.

I ordered one from him, haven't got it yet, I hope I don't have these problems.  Fixing to send my Avenger 1100 back to pyramydair

[mikeiniowa]

he made a mountain out of a mole hill and is happy with it now....

[Jaymo]

Well, Mike, my B40 I bought for you is still a joy to shoot. Though heavy. I'm going to have to shorten the stock by about the thickness of the recoil pad, to get the length of pull right for me. I removed the pad and shot it for a while and found that I was shooting it much better that way.
BTW, how much for a MM tuned B28 .22 tuned with Maccari seals/tune kit? (full  power spring, please)

[jberenyi]

mikeiniowa - 8/18/2009 8:36 PM he made a mountain out of a mole hill

Hhmmm....I didn't think I did.

[cnsjones]

Just my opinion:
In the airgun/firearm game as in a lot of others, where there is a mechanical contraption involved, and where the work of others is involved in the repair/fixing/preparation (read TUNING) of the contraption, one should give the person doing the work a fair chance to "make it right" before getting all bent out of shape.  I know this is difficult at times, but we should remember that parts used CAN be defective, and the other person's time and effort is also involved.

 Right, we can decide never to buy one of the errant contraptions again, and also never to use the same source -- this IS a free country!  But the other party deserves credit when he/she/it makes an effort to "make it right."  Like I say, just my opinion.

[tjk]

Amen to that Fuller! John,...I think the trick to these tuned Chinese shooters is to shoot them alot!!!! I had a few qualms with my B-28A (.22) at first,...and it took a little effort on my part to get it to where I wanted it to be. At the present,...I wouldn't take all the tea in China for this weapon now!!!! I thank Mike for his guidence and support throughout the ordeal,..and it made me a little more springer/AR "savier" in the end. Knowing your rifles and how they work is key to making them perform up to your expectations.If you spend +$500 on an AR, sure it ought to perform flawlessly  out of the box,....but considering the fact that Mikes Chi-clones are ALOT more inexspensive,...you have to do your part as well. Even the low end Beemans (HW's) and Dianas need some help,...but if anyone's going to improve them,..it's up to each individual to take on the task,...be it a DIY tune, a "Pro" tune,..or just adding a little lube' here and there' post-tune refinements. Personnaly,....after a minute amount of dremil work to the stocks' internal rail,... all I did was dab a bit of moly/tars where I thought it needed,...and then shot the living hell out of it. Other than that,..the gun basically fixed itself!!!! I'm a proud owner of two MM'd  B-28's  (the Diana clones), ...I did my part,...and now I'm reaping the rewards!!!!! Anyone can,...if they do their job!!! Besides,..it's alot of fun too!!!  As for the stocks,..let's face it,..the Chinese rifles aren't exactlly as "pristine" as the German produced weapons', nor the tolerances,..but sooner or later,...you'll take it to the woods and add a few "memory" marks to it anyways!!! Scratch the action?!?, big deal!,...that's what they make 'touch-up' blueing  for. I keep no "safe queens" in my arsenal! tjk