Bren and again and again

Test fired the Bren today and it fed beautifully so I moved on and made another mag and tested that one and it fed perfectly as well .
One more mag to go and a little paint touch up and I'm finished , just waiting on Simon to get back to me about the gearbox upgrades and she's finished !

Took a break from Bren mags to do this SA58 monstrosity that Simon wanted as well .

A nice pile of goodness for the gearbox .

it was shooting 287 fps , now 363 fps , its going to settle down a bit over the next few days and should be around the 350 fps mark after .

For some reason i am never lucky with springs they never give me jules marked on the packet,way over or way under fps,or some of the cheaper ones loose significant fps over time due to poor heat treatment.Then it means several strip downs to get it site legal,some sites wont even allow half an fps over limit.
One Tech told me if you shorten the main spring it can cause it to have a large power deacrease in use,but i dont see why that would ,the main reason to avoid cutting a few coils of is you no longer have the flat end,so e advise against this too,although sometimes you have to.

I've cut coils off many times ,with variable pitch springs I cut the close together coils and grind flat on a bench grinder , as long as there's no sharp end and you put the cut end in the piston then your fine , if you have the cut end of a spring on the sprig guide it can unseat its self and have the end stick out and foul the piston .
Its always trial and error if you want to get as close as possible to a site limit , the other thing is to let is rest once assembled , leave it for 24 - 48 hours and then crono it ,all springs that I've used have lost around 10 fps in the first 48 hours .
If you are a shop tech and use the same brands of parts repeatedly then you probably get a pretty shrewd idea of how a gun will perform but for us who build up only a few guns a year its a lot harder , some years ago now I made up some adjustable length spring guides to fine tune with but these days I'm happy enough with 330 - 350 fps and don't need every gun to be 349 fps exactly .

Where I work, we cut springs a lot of the time, mainly aiming for around 340fps trying to keep under the 350mark, because of difference in chrono’s on different sites.
I’ve even had guns go up on fps after a few days, probably as they settle in but most come down some. Different make springs of the same same power do indeed differ, I try to keep track in a book, what makes, aligned with barrel lengths will roughly do in certain guns. Life is a bit easier with most newer guns now coming in with quick change spring facility.
I do much the same to finish off the spring when cut, grind off flat and with a small flame tweak down to line up and while still hot a little dip in the oil.

I find that grinding flat heats and de-tempers the end of the spring enough to bend it flat with pliers if needed , sometimes you have to clip off so much that you go into the wider spaced coils and then you need to flatten it for sure but mostly if you stay in the closer spaced coils they tend to close up mostly flat under compression .

Last magazine finished , I did forget something though , the carry handle should lock out to the side of the gun for "from the hip" shooting action so I need to fit a little ledge on the side of the gun for it to lock to . still shooting hot so it needs a little spring trim after all .

Some Bren gun doctrine here
https://m.youtube.com/watch?v=LLd0Px2Q8E0
Dont know if you have heard of bloke ,but he seems to know what he is talking about ,and uses source material to get many of his facts.
His video where he talks about what Americans have put over as facts anout the Enfield Rifle in recent years,all internet hearsay,bloke points out that all the countries that used it as a service rifle never noticed those Facts,made me laugh

That clip shows a nice demonstration of gunner and loader doing magazines change drill , thanks for linking it

Cool so now you are intriduced to bloke on the range,he seems to get some stick for not. being some super cool ex delta force type yank,but like i say seems to know what he is talking about ,he seems to be some kind of gunsmith and competition maksman with some military experience,even if it was only at cadet level

A little update , Simon (Fremsley) dropped off the bipod and one of those Commando front grips , i confess the Commando grip is one of those things I was not keen on ( a bit too Schwarzenegger ) but now its fitted i like it , makes me come over all Chindit . All that's left is a little downgrade then a final coat of paint so its all shiny for Simon

Its now shooting 330fps and its all in bits for hopefully the last time , its had a last lick of paint except the front of the barrel and is drying in perfect drying weather , the battery's arrived today , it should all be ready for Friday/Saturday hand over