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Benjamin Maximus multi-shot breech?

I’ve got a fortitude g2 (my profile pic) but seems like the tube was not going to work for my pumper, I believe when I had it apart last summer it was vented for the regulator or something.... don’t recall exactly what the thing was that made me decide not to use it. Anyway I have a Maximus due to arrive Monday for the multi-pump project . 
I bought an exclusive shop breech for my Prod and wasn’t happy with it and wished I hadn’t bought it. It was shipped in a thin padded envelope with no additional padding of any kind, so the corner of the breech was damaged in shipping. The pin in the side lever linkage is very loose so it starts to work it’s way out when you work the lever and gets hung up trying to close it. This was obvious just taking it out of the package upon receipt. I didn’t even try to install it on my Prod. Figured it was a waste of time because it was obvious it wasn’t going to cycle correctly. I complained to them about it and they’re response back was it was all go when they shipped it. They have no intention in making it right. They can go pound sand as far as I’m concerned now.


It’s more expensive but this is supposed to be a much better breech than the Exclusive Shop breech but I have not bought one personally. you do have to turn down the barrel to fit into the breech because it is a tighter fit.

However I personally don’t think modding the single shots guns to be multi shot makes a lot of since. at least to me. Better purpose built multi shot guns out there. A Prod, Fortitude, Marauder, or any of the new Kral built Cayden, Akela or Kratos would be better choices in the Crosman lineup for a multi shot rifle IMO. With exception to the Cayden and Kratos I own all the ones I mentioned including a Maximus and several other 22xx and 13xx guns and I just personally would not do a multi shot breech mod to the single shot guns. 

Thanks for the input. I’ve used BNM multi shot breeches on builds before and they were a decent product. I could disassemble one of my discovery projects and use a BNM breech, but I don’t think that is necessary. 
I too have a room full of airguns, many thousands of dollars spent on them. I am currently building a multi pump rifle, and the Maximus is going to be the platform I’m working with.
The GMAC units look to be a copy of the BNM to me but not as many flavors as were available in the old BNM. I miss the BNM for sure. I have used the rather spendy Custom Air units. They are the Cadillac of breeches as far as I am concerned such a smooth action. They DO require the breech side of the barrel to be thinned down near .005 inches, if memory serves, to fit though. 

I did a rather lengthy post on the differences and installation between the Exclusive with it's very sloppy linkage and wonderful Custom Air breeches a year back or so. I went to update one of the pics and the whole thread disappeared never to be seen again. ;^( Maybe I will do it over someday.

About 6 months ago I installed an Exclusive Multi-Shot Breech on a P-rod

There were no issues with fit, finish, or performance other than a sloppy linkage pin; which I will get to fixing if it ever really begins to bug me.

I also bought one for my Maximus at the same time, but have not yet installed it. (This winter??)

The only downside is that there are no instructions or advice included

The one question I had was answered promptly, however

Hope this helps


I sure would like to read your comparison of the different manufacturers' breeches.

To me they all look like re-labeled clones


Anyway just to agree with you and stating some personal facts...

I have put together several cool projects starting with Benjamin Discoveries a long time ago that ended up costing the $220 starting rifles roughly $1000+ apiece after B&M multishot breech and shroud and Maraider Trigger kit and power valves and custom stock. Regulator did not help so that price wasn't added to the $1000 apiece prices.

You get to save $100 because the Maximus is cheaper.

I have a duked up Maximus version too that was a little cheaper till I got my first $300 Hatsan Flash rifle then reality sank in.

Fun projects no doubt. I would not have done them (at least no more than ONE) if the Hatsan Flash rifles were available during that time.

Even after you have the thousands upon thousands of dollars to blow back then it kinda hurts when you add it all up when looking back. I could never even come close to recovering my money if I sold them.

That's not the biggest money pit which was an Armada that ended up roughly $1300 and not even regulated. Funny thing it shoots more accurate with the power cranked all the way down defeating the purpose of the upgrades parts. At the end of the day it's still a Marauder with tactical stock and yes real fun at the time but that DIY hot rodded Honda Civic TYPE-R could have been a Mustang GT500.
I have heard nothing but praises on the exemplary finish and machining on GMAC parts.

Their multi-shot breeches are quite pricey though at around $160 shipped to the USA.

That's not an outrageous price considering Exclusive is charging $130 shipped on eBay, & the CutomAirShop version referenced above by MileHighAirGunner is over $200

I wonder if anyone can tell us if the GMAC breech requires lopping of some of the barrel just beyond the transfer port, as does CustomAiShop's


PLUS voiding a 5 year warranty off the bat?

Well at least it's not a $2000 FX IMPACT voided warranty like all them DIY guys.

When you can fix your gun yourself and would never ship it away for someone else to do what you can do. At that point the warranty is worthless other than warranty supplied parts. Competence is key.

Not every manufacturer voids warranty from self diagnosis and disassembly. Fx is one of those companies as they will literally send you parts under warranty.

Yes yes Odoyle....I am rich because I hack up cheap crosman airguns. Try to refrain from insulting your betters. I’ll pardon it this time. 
If you do not have any actual useful information please do not feel compelled to join conversations compulsively. Making noise in a conversation is not valuable.
Every post doesn’t need christened with the Odyle stamp of approval. 
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