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Slingfire Upgrade

I've got a Slingfire coming in the post, and a 5kg spring sat waiting to be used. Thanks to Blastersmiths I know about gluing the slip clutch mechanism to deal with the stronger spring, but was wondering about the feasibility of using a screw to hold both pieces together, on top of filling it with glue. I was thinking once glued together drilling a small pilot hole through the pair and using a screw to self tap into the plastic. I just want maximum security on this, that's all.

Also, while I've read that the gears are more robust than others (Roughcut, I'm looking at you), does anyone have any experience with just how resilient they are? Would it be possible to put a bigger spring in the system, say a 7/10kg, or is it going to self destruct under that pressure?

No experience with 7-10kg spring loads other than the BSUK spring is actually 6.9kg and the Winchester is still going strong after a couple of years.

You are correct, you can bolt together the gears if the Devcon fails. I think we had a batch batch of it so CarrierII took an M3x10 and associated locking nut to the problem and solved it that way. I don't have pictures nor am I permitted to open it. If you know the Slingfire I'm talking about then you'll know why... Wink

A 10 will definately break something, not the clutch if you mod it right but the next thing in line. Also cocking it repeatedly with anything higher than a 5 in is bloody hard work.
The gears are fairly sturdy, the pins that hold the gears into the box are cheese grade plastic. In the aforementioned slingfire I replaced them with brass pins, cut to length from correctly sized rod. There are two different lengths and mixing them up stops the gearbox closing properly, so photograph/measure both to ensure they go back in correctly when you make new ones.
I wouldn't run more than the BSUK 5 kg in it. You can get 100fps out of that already with the AR out. Be aware they are a bastard if they lock up, with opening the only way to clear really bad top hat jams. They are fun but I wouldn't describe it as a war winner. Mine has been gathering dust for nearly 12 months and I am a fan of the Slingfire.

OldNoob wrote:
They are fun but I wouldn't describe it as a war winner.

Yeah, I'm intending to turn this into a Winchester-esque rifle jobby that will mainly be for plinking at home rather than being war practical. My worry was that fitting a long barrel is going to massively increase drag and slow FPS right down, so was aiming to overcome this with increased spring power. I'll start with the Blastersmith's one and see how I get on.

Likely this will be like most of my projects; I do a bit, get distracted, and shelve it for a few months!

Fit fluted faux barrel. You will lose about 5-8fps per retal barrels length at standard faux barrel bore.

I dont know if it helps or not if your glueing the clutch up anyway,

but ive seen the 3D printed blocks that replace the little spring loaded chock blocks inside the clutch disintegrate.

I replaced them with stock ones again but cut down a small nail and nested it inside the springs to keep them locked out.

Well my Slingfire turned up and itís been an experienceÖ.

Fixing the slip clutch was a doddle: I went for a combination of superglue (I donít have any Devcon or epoxy) and some plastic wedged into where the springs go. Itís solid as a rock.

Removing the AR was a bit of a ballache, but a combination of Dremel and drill finally got the entire assembly out.

I fitted the Blastersmithís spring, but it comes up a little short compared to the stock one. Itís only a few mm short, but I found that at times after firing it will pop out of the black spring retainer at the rear and cause the blaster to jam up. Iíve got around this by adding a washer to compress the spring a little bit (well, about 6-7mm) so that itís never fully extended. I found that the standard internal barrel tubing is exactly the right diameter to allow the plunger rod through the middle, but still hold the spring up the rod. Iíve mounted the washer at the back of the plunger head, rather than inside the spring container: doing so only means the spring is seated in a 1mm recess so can still slip out and jam up when primed/fired.

I also had to seriously sand down the mag release catch because it wasnít chamfered enough to allow a mag to load unless you pulled it back or really smacked the mag in. Also chamfered some of the corners inside the mag release lock and packed it with grease to give a smoother operation.

One further question I do have is in regard to the various locks that are in the blaster. I want to keep most of them, but the forward most lock that pushes up into the barrel tube until the blaster is fully primedÖ. What does this do exactly, other than get in the way and make priming tricky? Thereís already a little swing away gate inside the barrel that acts as a post for the darts head to push against when the breech slides over the back of the dart, before being moved to open by the bolt sled returning to the forward position.

DO NOT REMOVE THE DART TOOTH, it's there to push the dart back into the bolt properly. With the AR in it engages that fully (we don't bother removing AR's in modern stuff usually) but with it out it is still essential to prevent air loss around the dart on firing, as the bolt fit tightens further back. The dart gate (swing part) is not strong enough to load the dart properly on its own, it actually pushes against the tooth.
You had to sand/re shape the bolt because you altered the priming length with the spacer.
The forward bolt lock (one that holds the breech closed until trigger is pulled) is worth taking out on the SF because it means you can open the breech in the event of a top hat jam, which is the most common cause of stoppages. It doesn't matter that the breech isn't locked shut because you only fire with the action closed due to the lever needing to be forward to hold it!

I had the trouble with the mag release catch even before I replaced the spring or fitted a washer. I think the problem is it is too wide as standard, so catches on the top sides of the u-shape cutaway on the back of the mag, rather than being pushed backwards. It's now got a more V-shaped profile so doesn't catch the top of the mag cutaway. The peg on the back of the catch that slides back in to the channel that's opened in the lock when the prime is fully forward is a snug fit as standard, and even though you can have the prime lever fully forward (IE past the last "click") it was still not able to move into the channel unless the lever war held right forward. Rounding the tip of the peg off and greasing it up has made it work a lot better.

The prime length appears to still be the same with the spacer fitted. If it was shortened then the toothed sled "track" wouldn't be able to go back/forward far enough for the little pivoting lock to stand clear of the teeth at either end (that little grey piece that sits on the outside of the clutch housing). Without the spacer in neither stock or BS' spring was getting fully compressed; with the spacer in it's pretty much fully compressing either spring (I reckon I could go another 1-2mm on the spacer).

The dart tooth has gone. Bugger. I made sure I left enough material inside the bolt to make sure the dart can't be pushed further back and into the plunger. I've noticed maybe 1 in every 15 darts be a flopper, but I think that's as much to do with the quality of dart than anything else (all Elite's; some new, some worn/squashed). Would it be worth pushing a tube of the usual ID brass (I'm guessing 5-10mm thick) to give a better seal at the base of the dart?

Yeah, the forward bolt lock is the part I'm thinking about taking out, because it just seems to cause more hassle than it's worth.

Now the tooth is gone unless you fully brass breech it you won't gain anything from putting any brass in the bolt, as you will have nothing to push the dart back against. The 1:15 flop fire rate is entirely down to the lack of dart tooth. More worn darts are not pushed as far back into the bolt, so they drop out.
If you want game worthy performance a full brass breech or restoring the dart tooth are your only options.

OldNoob wrote:

If you want game worthy performance a full brass breech or restoring the dart tooth are your only options.

Thankfully this one's only ever been intended as a plinker. Though I'll bring it along to BB to run a few on the chrono to see how it performs, and possibly use it for some HvZ silliness.

Any idea if there's a blaster that I could just swap out the entire bolt with? I've got quite a few blasters sat at home that I may be able to sabotage something from

The bolt isn't your problem, it's the breech and dart tooth you need. Try the dart tooth from any elite springer. Where did you throw the tooth? Ferreting through the bin is easy vs trying to tag anything without a dart tooth.

The breech and bolt is fully sealled with cement, so I just drilled the AR and tooth out together.

The tooth is what is infront of the gate. It has zero to do with the AR.

Properly annotated picture!

I was beginning to wonder....

You had me confused when talking about the dart tooth engaging the AR. I though you were on about the dart post which forms part of the AR system inside the bolt (the post that goes inside the hollow of the dart): that's the bit I drilled out entirely.

I had a brief run through the operation of it last night, and if it's primed fairly quickly the dart will seat in the bolt fully, no issues, just by pushing on the dart gate. If it's primed slowly then the gate opens up and the dart is pushed through it; sometimes quite a bit, other times just a few mm - either way enough to noticeably reduce firing velocity. I'm still noticing that darts that are worn/flattened slightly at the rear still flop, even when manually seated into the bolt.

Thankfully I still have the dart tooth, so I can pop that back in no problem. I'll hopefully get a chance over the weekend to have a tinker with it and see how it all operates.

Every day's a school day!

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