I made sure the barrel was fully seated by turning over the breech and looking at the alignment of the TP holes. Below is a photograph of assembly when looking at it through the TP hole from the bottom side of breech. You can see a little of the probe tip. In this photo I didn't load a pellet. I was mostly inspecting the interpart relationship of the TP assembly.The earlier photos sure look bad... this one not so much. For full clarification can you do one like this with a pellet?
Despite the test, my fundamental education in engineering and physics dictates the position is bad. I can see how easyly the HPA flow can collapse or damage the skirt.
Thinking about this more. My guess is that someone might not paying attention to parts upon assembly. They might just be simply interchanging parts. This most likely is specific to the side bolt version of that breech. Without a comparison of parts' dimensions, the clear picture of the defect or issue in not known.Here's a shot in the dark... keep in mind I don't have the side bolt model to check. Check the bolt, Is it possible that the cocking handle and the threaded Allen bolt ( the one that cocks the pin on the hammer) are the same thread and maybe they inadvertently were switched? (Assuming one may be slightly ahead of the other)
Regarding the picture with the pellet in the barrel that is has the c stamp. Yes someone at BNM turned the wrong end. I own 4 BNM breechs, 2014 I sent a LW barrel and one of the breech. When I got it back I was in the same boat c stamped on the breech end. I called LW and confirmed it was indeed wrong end.
Sent it back they ordered and cut a new barrel blank. So they should know better. All bolt probes left the pellet in the center of the TP I've told Sergio about it. I went ahead and made new probes for all.
Another thing to be aware of is the bolt handle is made of soft steel of some kind. I've broken three bolt handles and shot one hole in my deck roof. I just buy another bolt handle for all my breechs. For what it's worth even with the few problems I've had I'd still buy from them.
Wouldn't want to take your money. I checked for the choke when I got the breech and barrel back from Sergio the second time. Not going to assembly a rifle if things aren't right.
Sorry Boss but you have it wrong, All Lw barrels are stamped at the Breech Not the Muzzle, So your barrel is in fact Not choked at the muzzle as it should be!! Push a pellet through where is your choke, I Bet it's not at the Muzzle like it should be. Unless you sent them a crosman LW barrel witch are Not marked.
Jay, we are not supposed to bash people or companies on the GTA.... Making people aware of a problem is one thing, but I would be careful with your comments or the Mods will be all over you.... JMO....
Bob
Well, &^^&....Just got mine in today. Installed it on my Maximus, looks great, but lost 50 fps. I am not taking it apart just yet. I will be watching this topic to see where it goes. If I had only waited a week or two..... Figures!Mine was down on fps as well. I found that the bnm transfer port while nicely machined, wasn't long enough. Used the ice maker tubing trick.
ACZan Your all Good, I went Rounds with this BNM Custom's, Fellow 2 years ago with another problem of poor parts fit. PayPal sided with Me ;D ;D I However Sent his Items back Anyway! With a Nasty Letter about his Machining Practices and Tolerances, And Now we have More Problems again!! Sergio Just don't get IT!!Just out of curiosity... what were your "rounds" with bnm? I did a lot of research before I ordered my breech. I wasn't even sure if they were still in business because they didn't get many mentions in the past couple years.
Okay, Guys.Ha!... I was posting when you posted that. Like I said above , it's like it was possibly indexed wrong in the mill.
I thought it wouldn't take very long after I sent the same message to BNM Custom as I did to MNB Aerospace that I would get a response. Especially after the way I worded it. Below is what I just received seconds ago.
Hello Chris
Could you send the breech back to us it seems like the block has some issues the barrel should go all the way in that is why doesn't clear the pellet Let me know thank you !!!!!!!
---
BNM products and services Inc
John
Gotta remember if you move one thing, many other relationships in and amongst the parts have to change, too. There is enough room to lengthen the probe and still have it fully retract from the magazine. I mentioned this early on in the topic. There might be references over in the chamber-leade topic from which this topic was spawned.How much longer can your bolt probe be made? Like I stated above mine can only be maybe another 3/32"
Look at page one near the top. I took a photo of that pellet still attached and retracted. Looks like a couple of pellet lengths of room.Huh... well than I guess you know your problem. I still say it's not the probe but with the breech block machining itself. I'm glad you heard back.
Just measured it. Looks like the probe retracts about 5/16 of an inch into the recess back away from the magazine/opening.
Proz83,
Yes, there is supposed to be an o-ring there as show in my photo uploaded in another topic. But, will put it in here if there is no problem having it in a couple of places. There are some folks who didn't know there was an o-ring in there. You have to look closely as it is hard to see it at times.
By the way, mine is a rear bolt also.Man oh man... that stinks... mines a rear bolt and it completely clears. This is using crosman premiers brown box. Can you do me a favor and measure your bolt? Mine measures 3-5/8" from the tip to the rear. When pulled all the way back how much space between the tip of bolt to the face where the magazine goes? Mine has about 3/32".
I usually use CPHP in 14.3g. I believe that I understand what Bob said, but don't agree with having to change pellets. Shouldn't the probe push every pellet pass the port, if their skirt length is the roughly the same size ?I completely agree... it should push the pellets past the port. Not that it should matter but some pellets have a deeper probe pocket than others.
| |Member| | |Bolt Type| | |Measurement| | |Port Coverage| | |Notes| |
| ACZan | Side (.22 Cal) | 3.3000 | Bad | (shrouded & non-shrouded) Length in front of bolt handle to probe tip 1.56" |
| Kmaz | Rear | 3.625 | Good | None |
| Proz83 | Rear | ? | ? | ? |
| Mudbugmitch | ? | ? | ? | ? |
| KnifeMaker | Rear | ? | Bad | ? |
Well at least your getting somewhere, I would make sure you get a tracking # when you ship it back. So they can't say you never sent it back!
Same here. Just saw a breech from Thailand.....I bought a black one from him 5 days ago.i needed one in .22 and like that it's a lever instead of a bolt. Also bought his adjustable valve. Rabbit hole is deep!
Guy's $160.00 for a breech that will still be as unstable as a OEM Crosman breech? The only thing that I see interesting is the side lever.Crosman repeater breech Unstable?... Huh? Side lever should be better for heavier springs. Will it be? I'll find out. The money we spend on these is all subject to question. People spend $150 on a valve or an aluminum tube. $130 on a repeater breech is money well spent if it performs well.
Still no tracking number from BNM. This is getting old, quick. This should be real simple, Send me a new working breech, Send me a tracking number and a return postage sticky. I will return your defective breech. SIMPLEThe may have to finish it. They might only inventory raw machined product. People chose the color option.
Thailand breech, I would be concerned about that Side-lever ??? That is clearly cast, And not a good looking casting at that. It should be made from solid Billet aluminum. I also don't like the fact they don't show the Bolt Probe ;)I said I'll find out... 6 pages of bashing one brand and you'll bash this now too? Cast doesn't mean it's bad. Give it a rest.
Guy's $160.00 for a breech that will still be as unstable as a OEM Crosman breech? The only thing that I see interesting is the side lever.Crosman repeater breech Unstable?... Huh? Side lever should be better for heavier springs. Will it be? I'll find out. The money we spend on these is all subject to question. People spend $150 on a valve or an aluminum tube. $130 on a repeater breech is money well spent if it performs well.
Kris
You may be correct... I havnt had a problem. 14.5" barrel carbine.Guy's $160.00 for a breech that will still be as unstable as a OEM Crosman breech? The only thing that I see interesting is the side lever.Crosman repeater breech Unstable?... Huh? Side lever should be better for heavier springs. Will it be? I'll find out. The money we spend on these is all subject to question. People spend $150 on a valve or an aluminum tube. $130 on a repeater breech is money well spent if it performs well.
Kris
All the 22xx breech's that i know of still depend on the minute 4/48 screw in the loading tray or under the bolt to hold the breech down and compress the T/P. When a rifle barrel is added to it, chances are it will have a problem holding P.O.I. that's why so far the remedy has been to use two barrel bands. The Tai breech doesn't look like it uses any barrel band and the bore centers don't look like they will match O.E.M. So now where will the barrel bands come from to keep everything glued down?
Well I may as well join in. I too lost over 50 FPS with the BNM. Overall I'm happy with the fit/function, not happy with the loss in performance. In my case I have an aggressive leak at the transfer port and the pellet of choice also just slightly covers the barrel port. I don't really have room for extending the probe and if I want to machine the channel further for a deeper push I'd have to make a new bolt anyways since it bottoms out on the back of the breech.I'm confident if you replaced the aluminum tp that bnm supplies you would surely make up that 50fps. In my limited experience messing with it, if you can feel air leakage it should deff equal at least 50 fps. I believe I used 1/4" polypropylene tubing. Same tubing used for refrigerators or r/o systems.
All that being said I'm curious to see what the fix is for this. Anyone have any ideas for sealing up the transfer port? It almost blows what's left of my hair back when I touch it off. I see nothing that actually places any preload on the seal in the exhaust port of the valve (the transfer port will slide well up into the transfer port block, I'm assuming the shoulder is supposed to time out on the opening in the transfer port block).
(https://i.imgur.com/RBkUNtB.jpg)
(https://i.imgur.com/8n6TUIM.jpg)
Imadunatic,
Is that a rear bolt. Can you measure the length of the bolt and post it on a reply?
Mitch, did you provide a measurement of your bolt? Also, I haven't received anything from BNM Custom, either.
Below is a photograph of the bolt opening leading into the barrel. There is a o-ring in there. The non-shroud version of my breeches felt a little loose. Thought one or two people mentioned their o-rings were missing.
For any of you new visitors to this topic, please view the diagram cross section of the transfer port assembly. The TP sleeve of the BNM does not touch (seat into the counter bore of) the barrel. The TP sleeve in Crosman stock assembly does.
Imadunatic,
Is that from the very back of the bolt, including the handle to the probe tip? What is the measurement from the very back of the bolt in front of the handle (I would assume the front of the handle is considered a stop) to the probe tip? I think you guys with the rear bolts have to measure from the back of the breech where the handle rests up against it to the probe tip.
For my side bolts, the process is a bit different. In order for me to get my micrometer on the back an tip of the bolt, I had to move the bolt to its halfway point in the travel.
You were posting while I was typing my reply. That is a great drawing! What program did you use to create that?
Imadunatic,
Do you have a photo of what your port hole on the barrel looks like? Or, is it just the Crosman stock barrel with no modifications? Do you have the TP sleeve seating inside bore on the barrel port?
Yes, congrats on your success. You up to making anymore transfer ports ?
Mitch
Well I am pleasantly surprised.... Machined up a new Transfer port that is much tighter in every direction:sweet! It never dawned on me that their supplied tp should "seat" into the center block and not the barrel. That would make sense.i feel like mine didn't so it when tightening down the Breech it didn't force it into the main tube seal. Good job
(https://i.imgur.com/k0z6RSz.jpg)
and also added a needle probe that is .080" longer (it is perfectly flush with the breech when the bolt is completely retracted so I won't have any issues installing or removing mags. The air leak is completely gone and I actually gained 120 FPS... I wasn't completely interested in the furtherance of science I just wanted to get the 2400 back to shooting like I know it can (actually better than it ever has) so I didn't change just one item at a time and test (I thought I was done with this project, the test and tuning days are behind it!)
It's now sending the 10.3gr heavies at ~880fps which is just shy of 18 FPE. The best I had ever done before the BNM was 830 with the heavies.
Unfortunately, I changed three things, not all of which are accessible to the average cat:
- Installed .060" needle probe (stock BNM was .080)
- Machined up new Transfer port that is much tighter
- Extended probe tip .080" (flush with breech when fully retracted)
Ironically, the reason I had dropped the cash on the BNM kit was so it would just work.
Chris,
Bone stock on the barrel port. The secret sauce to these BNM TP are that they actually register against the shoulder and compress slightly against the exhaust port seal
So, Kmaz.I presumed that is what everyone was doing until the other gentleman said he couldn't screw his onto the tube because the tp block hindered screwing it down. Keep in mind I'm using tubing for tp so I have to because the tubing is locked into the chamfer in the barrel through the tp port block. once the unit is all together I insert tubing from underside. Once tubing is installed the barrel cannot be removed from the breech without removing tp. Install on tube trimming tp to fit. I don't know how to post pics... should learn. But can text or email.
You are putting the breech body, TP block, TP sleeve and barrel all together before mounting the whole assembly to the air-tube. So, what did you do special to accomplish that? Would love to see a photograph(s) detailing what you have accomplished.
I should follow your lead on this as that is what I'll try to do.
I have more things to add here but my sleep medication has different ideas at the moment. I'll post them tomorrow.
Kmaz,I'm able to completely insert or remove the screw at will with it completely assembled. Is that 5/16" behind magazine slot measurement taken while mounted and actually cocking the hammer? Because mounted and unmounted yields different measurements.(bolt cocks farther without hammer)
That is good to hear. If you can do the factory stock assembled way, then I should be able to do it, as well. Initially, I thought there was enough access to get to the screw head. Will the screw go into the hole with the block installed? Or, did you have to take the block off just to insert the screw, prepping for the assembly?
dealing with a potential safety issueWOW! Now where did that come from? I'm posting as just a member not a moderator at this time.
Thats a lot of maybe's BOB. I am only concerned about one. Mine.
I agreed to send them the breech if they do what they said. I still will, still waiting. Ball's in their court.
11 business days seems sufficient to me, they got my money in seconds.
But I will stop my Rant, to ease the tension.
I am gonna sit here and play mushroom and see how this plays out.
Patience is not a virtue of mine.
Good luck to everyone concerned.
Mitch
Sfttailrdr46,No I Imply nothing what I said and will say again is that if the bolt was installed properly and the pellet does not insert slightly forward of the transfer port the greatest risk is poor velocity as long as the bolt is locked in place the full charge of air released from the valve will not propel the pellet to the proper velocity since some of the air will most likely blow back through the breech seal not propel the bolt out of the back of the breech
The rifle to which I am referring is a an unmodified out of the box rifle, if you are implying operator error. Too much room for chances on a defect, ones I wouldn't take. I have see what happens when projectiles fail to take their intended path with high energy forces behind them.
3, 2, 1
::)
Jay, we are not supposed to bash people or companies on the GTA.... Making people aware of a problem is one thing, but I would be careful with your comments or the Mods will be all over you.... JMO....
Bob
I understand Bob but this Gentleman's Company {BNM Custom} IS Not A Forum Sponsor!