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sharpshooter · New Member

Just purchased a SMKXS19 and apart from the clunky recoil am pretty impressed with this gun for the money,but wanted to change the spring to increase the power.As its a pretty new gun on the market i cant find any shops that list a spring to fit this gun,does anyone know what size spring will fit and how much i am likely to be able to increase the output by??Also what else can i do to increase the power of this gun,all feedback much appreciated,cheers.

AirGunEric · Site Admin

You have a BAM B19- which in more modern terms is also known as a Crosman Quest.

The same platform (mechanics) are what is in the Crosman Quests, Phantoms, G1 Extreme and Tac-1 guns.

That being said- Crosman bought the rights to the platform for North America- as in no one else can sell a "B19" in this part of the world except Crosman. You guys in the UK are either not part of this agreement, or vendors are still selling off old stock.

Either way- any of the improvements that would work on a Crosman Quest also work for your gun- better springs, thrust washers, better barrel/receiver bushings and so on. I don't know the configuration of your gun specifically- what caliber is it and what is it's advertised output? That would give us a better idea of what is in there already, and where the improvements can be made most efficiently. Is there any way you can identify exactly when it was made as well (i.e. month and year)- this would also help determine which parts are inside.

sharpshooter · New Member

Thanks for the feedback,i thought that smk guns were made by the chinese,i must be wrong according to your answer,so what your saying is that this gun isnt actually made by sports marketing(SMK) and is in fact a crossman with an SMK label on it??? It is a 2.2 calibre and the stated muzzle velocity as standard is 12lbs

sharpshooter · New Member

Apologies for my thickness,i jus searched for the BAM B19 and it is the same rifle,i now get what you were saying,cheers.

AirGunEric · Site Admin

Just so we're on the same page- Crosman doesn't make the guns I mentioned with those names on them- they are made by "Best Airgun Manufacturer" in Shanghai, China. The Crosman versions have been customized as per Crosman's requests to BAM and BAM has agreed not to sell any of their guns of that design through anyone else, at least not in North America. The BAM B18 and B19 were available for sale in North America as well prior to Crosman making this deal.

That being said- Crosman does do some "final assembly" on the G1 Extreme and Tac-1 models in the United States- what this means is that they put on the muzzle brakes and in the case of the Tac-1 the accessory parts as well.

From what we've been able to gather about SMK in the UK/Europe- they are an importer of Chinese airguns (for example, the B19) and they may do some partial assembly in the UK in order to avoid certain duties and taxes, then label the gun an 'SMK XS 19'.

The newer Crosman guns have had improvements done to them within the last year- but I do not know if the SMK/Chinese guns also have the same changes, or if they were only used on the Crosman guns. For example, the newest Crosman's have heavier, thicker pistons in them, trigger frames that are a bit more secure in the tube of the gun, better barrel/receiver bushings, and a modified detent spring for the barrel lock. If you SMK has these already in them (and depending on it's output rating- the best piston)- the only real additions or improvements to be had are the spring, the spring shielding, a couple thrust washers behind the piston top, and a proper lube/tune job.

sharpshooter · New Member

Thanks for the info,the origin of my gun is much clearer now.As for upgrading the spring,i was looking at the ox springs but cannot see my rifle in the list of springs to fit it,the closest i can see as far as dimensions go is the number 2,will this spring fit my gun??Many thanks.

AirGunEric · Site Admin

"Ox springs"- which are these? Do you have a link to them?

sharpshooter · New Member

http://www.sportsmanguncentre.co.uk/productDetails/Accessories_Airgun+Accessories_Targets/OX+Main+spring/

http://www.airrifleshop.co.uk/Accessories/Springs.htm

AirGunEric · Site Admin

The number 2 spring appears to have the correct length, give or take- but here is a link to the spring used by people in North America:

http://www.airguns.citymax.com/catalog/item/251488/43410.htm

Which is a spring that is 11.75" (298.5mm) before being 'set' by the gun. Once 'set' it is 248mm in length. It has an ID of 13.5mm and is also typically used in HW77's and HW97's. If we look at those Ox specifications, the #2 appears to have the right length, but it's inner diameter might be a bit tight for the spring guides(?). Based on the application listings, and comparing this to the U.S. spring- it appears as though the #6 Ox spring would be the "match" although it is quite a bit longer (I'm assuming this is likely 'unset').

It would be useful to know if those length measurements are pre-installed (unset) or after installation (set). If we can determine this, it would be easy to decide if it's the #2 or the #6 spring. Any chance of calling or emailing a vendor to see at what point that length measurement has been taken?

sharpshooter · New Member

Purchased the ox number 2 spring and fitted it yesterday,was expecting the thing to fly apart when i took the retaining pin out but was rather dissapointed to find there was no pre load in this gun with a standard spring.
Fitting the new spring was a little trickier as it was slightly longer but with a bit of brute force against the edge of the table i managed to get it in.
As for increasing the power is awesome,at 15 yards it puts holes in house bricks and went nearly all the way through the phone book,you need biceps like arnold to cock it,i wanted to get it on a chrono but the shop advised me that if it is over the limit they wouldnt be able to hand me back the gun without de tuning it so,i will just settle for knowing its pretty powerful,so them king rats at my local lake can look out now. Mr. Green

The only thing im concerned about is the extra strain its putting on the trigger mechanism being a single stage trigger, is there an upgrade i can get to fit this gun?
Also the measurements on the ox springs are taken before they are put in the gun if its any help to anyone.
Many thanks.

AirGunEric · Site Admin

OK- if those are the spring length's before being installed and the #2 worked at 248mm- it must be "pre-set". If it wasn't and it set even as little as an inch shorter (25.4mm) than the 248mm it wouldn't likely do much for the gun's output.

Based on the spring specs- I bet you are pretty darn close to 12fpe. If you are in the UK and want to remain completely legal- perhaps the shop that say's they'll keep the gun if it outputs more than 12fpe to detune it may not have to do anything, or very little. Just be sure to be there watching when they test it with pellets you know the weight of- so you can verify what they are telling you in respect to its muzzle energy.

As for the trigger- if you didn't change the piston itself or add any other "spacers" behind it (like a pile of washers or the like)- it should be able to hold the spring, but the rear trigger hold-down bolt (the one in-line with the trigger that the rear-most stock screw goes into as well) has to be in quite tight so the trigger housing can't be shoved backwards- if it moves even 1/8" that could disallow the trigger sear from grabbing the piston slot. The other thing to be sure of is that the trigger spring that pushes the sear/arm into the piston slot is also not weak due to age or use and that it firmly pushes the sear into the piston without any slop- otherwise it won't hold. You'll know when a problem is developing because the gun may start to not cock properly- you'll try two or three times before it grabs. If this happens, don't wait for it to not cock at all- get it apart and repair it.