Thread: BSA Hunter help required.

Originally Posted by Micky Duck

ok...so Im picking the shallow curve the striker? is sitting down on (looking at photo the way it is) is why the bolt "sits" nicely at half cock/bolt nearly all the way up and will stay there but not fire untill bolt handle is lowered,which looking at photo orientated the way it is will put the shiney bit over top of gap ,down the 45 degree bit to the right of the curvy indented bit its sitting in now??????????
always wondered how it did this.

Yes, when the bolt is lifted the 'shiny bit' climbs up the '45 degree bit' to 'cock' the action. The cocking piece then sits in the indent. Most bolt actions have a similar system but dont have such a positive indent as the BSA

Originally Posted by Micky Duck

ok...so Im picking the shallow curve the striker? is sitting down on (looking at photo the way it is) is why the bolt "sits" nicely at half cock/bolt nearly all the way up and will stay there but not fire untill bolt handle is lowered,which looking at photo orientated the way it is will put the shiney bit over top of gap ,down the 45 degree bit to the right of the curvy indented bit its sitting in now??????????
always wondered how it did this.

@Micky Duck my understanding of how these half cocks work is as follows:
As the bolt handle is brought down, the nose of the cocking piece moved out of the ‘cocked’ detent, and starts to move forward onto the cocking ramp. At the critical point, the cocking piece comes to rest to the sear, essentially ‘locking’ the cocking piece between the sear and the slope of the cocking ramp. The other part of this relationship, is that the bolt locking lugs need to have just the right amount of engagement with the lug recess faces. I believe part of the reason the BSAs do this so well is the slight relief on the leading edge of the bolt lugs.
It’s a very tricky inter-related clearance based relationship, hence there are only a few people around that can modify a rifle to achieve one of these 1/2 cock positions.

perfect...thankyou..... when I store my bolts I always turn the end so the shiney bit (LOL) goes down the ramp...two reasons
#1 it takes pressure off spring,learnt to do this after misfires when first got .223
#2 it makes it semi burgler and almost completely child proof...even if they got hold of rifle and correct bolt,eny meany miny mo, they could slip it into bolt race but it wont go right in and close,sure as heck wont fire.

perfect...thankyou..... when I store my bolts I always turn the end so the shiney bit (LOL) goes down the ramp...two reasons
#1 it takes pressure off spring,learnt to do this after misfires when first got .223
#2 it makes it semi burgler and almost completely child proof...even if they got hold of rifle and correct bolt,eny meany miny mo, they could slip it into bolt race but it wont go right in and close,sure as heck wont fire.

@Moa Hunter what caliber is this Hunter spoken about here?

Originally Posted by Mathias

@Moa Hunter what caliber is this Hunter spoken about here?

Well Mathias, she's got a serial number starting with 5B which from what I read confirms it was a 7x57 originally, and this is what I was told. It has been re-barreled with a very attractive fluted and blued 22 inch Weatherby barrel in 270.
Because the 7mil is a med length and the 270 a long action cartridge its future is likely with 110 - 130 grain flat base projectiles loaded short (have a box of partitions already) and in the interests of safety, just mild loads as it is not a super strong action, not to mention a pretty light rifle.

Interesting. 5B the Viscount medium for a 57mm case, a true medium length.

Sent from my SM-A530F using Tapatalk

Good fault finding. Looks like there is your issue!

On another note, I’m not sure that the viscount/Hunter actions were considered ‘soft’. As far as I’m aware they can be loaded to full .270 pressure.

Originally Posted by Hunter_Nick

Good fault finding. Looks like there is your issue!

On another note, I’m not sure that the viscount/Hunter actions were considered ‘soft’. As far as I’m aware they can be loaded to full .270 pressure.

Probably true re strength but the lugs on the hunter are smaller than the CF2 and these are smaller again than my Rem 700 which appears a much stronger action with the enclosed bolt head. Comparing them I would not like to put real snorting 270 loads into the hunter, besides it would kick like a Tikka if I did.

Do you have a measurement for a Hunter Viscount mainspring length. I dont want to cut the CF2 spring and find that it was a little off what it should be and I should have cut at 37 or 38 turns.

PS the hunter and CF2 have exactly the same diametre striker rod ( the rod that the firing pin attaches to ) but the tip section of the firing pin is shorter on the CF2.
So this game is a bit like re-building a SI or SII Landrover gearbox using parts from a Rover 90

Think CF2 only came in long action so only one length for spring? Viscount, medium length bolt, shorter spring?

Originally Posted by tetawa

Think CF2 only came in long action so only one length for spring? Viscount, medium length bolt, shorter spring?

Yes correct re CF2 action. I compared 36 turns of CF2 spring to 36 turns of Hunter and the Hunter spring is 22 mm shorter. Overall the CF2 spring is probably 50 mm longer than the Hunter but I didnt measure it.

Originally Posted by Moa Hunter

Yes correct re CF2 action. I compared 36 turns of CF2 spring to 36 turns of Hunter and the Hunter spring is 22 mm shorter. Overall the CF2 spring is probably 50 mm longer than the Hunter but I didnt measure it.

Comes a bit of a headache not Knowing the spring lengths when new. Hard to tell what has lost tension and by how much.

One thing to consider, you don't want the new spring to become coil bound when the cocking piece is in full rearward position. You could measure the donor spring when coil bound on the CF2 firing pin and compare to the length of available space on the Hunter bolt. I'm sure you have thought of this....just mentioning

Originally Posted by Mathias

One thing to consider, you don't want the new spring to become coil bound when the cocking piece is in full rearward position. You could measure the donor spring when coil bound on the CF2 firing pin and compare to the length of available space on the Hunter bolt. I'm sure you have thought of this....just mentioning

No hadn't thought of that. I was going to compress the CF2 spring onto the Hunter striker too see how much it could take, but that is not ideal as I could end up with an over compressed spring and slogging the firing pin attachment.
Bring on the suggestions - I dont want to balls it up

One thing to note.

If two springs are of the same wire and coil diameter and the same lenght then the one with the least coils is the stiffest spring.