Headspacing a new (SH) bolt.

[25 Sharps]

So, I am in the very unfortunate position of having lost the bolt for M595 25-45.

Variation has gone in and I have sourced a replacement that involves paying for a .222 (as was the donor action) to have the bolt only, with the RFD then scrapping the action and barrel..

I am aware the headspace should be checked and rifle reproofed. The rifle will never be sold so proofing not an issue as far as I am concerned.

Go no-go gauges are going to be a pain and I’m pretty sure the smith that put it together no longer has them.

If I go a little (more) redneck, and check for chambering on a neck sized round, then fire it and compare hard to shoulder datum measurements before and after, provided the shoulder doesn’t move too much (one or two thou?) is there really a risk of issues?

Will I cause any damage to the rifle or bolt doing so?

 

[enfieldspares]

It could if the headspace is excessive wreck your rifle as the gases from the ruptured base of the case blow out into your rifle's magazine well. However that will be found out at proof won't it...if the headspace is so excessive as to allow that. As I am assuming that the rilfe with the new bolt will be sent to proof before it is handed over to you? And if it passes proof whilst the headspace may be longer with the new bolt than it was with the old bolt the gun will be safe.

 

[Jager SA]

So, I am in the very unfortunate position of having lost the bolt for M595 25-45.

Variation has gone in and I have sourced a replacement that involves paying for a .222 (as was the donor action) to have the bolt only, with the RFD then scrapping the action and barrel..

I am aware the headspace should be checked and rifle reproofed. The rifle will never be sold so proofing not an issue as far as I am concerned.

Go no-go gauges are going to be a pain and I’m pretty sure the smith that put it together no longer has them.

If I go a little (more) redneck, and check for chambering on a neck sized round, then fire it and compare hard to shoulder datum measurements before and after, provided the shoulder doesn’t move too much (one or two thou?) is there really a risk of issues?

Will I cause any damage to the rifle or bolt doing so?

Pretty sure you could use .223 headspace gauges to check? If you get stuck message me. Rgds

 

[Malxwal]

Dunno about that era of Tikka, but I was informed by a reputable riflesmiths that Tikka bolts were practically interchangeable as the manufacturing tolerances were as little as .001 variance as regards headspacing.
Indeed, whilst troubleshooting an issue, we used three separate T3 bolts, and the fired cases showed no difference in size.

 

[25 Sharps]

Pretty sure you could use .223 headspace gauges to check? If you get stuck message me. Rgds

Thanks, for the offer, appreciated .

The thing is, this rifle always had a bit of an excessive headspace issue, which I get over by fireforming cases with a false neck. As much as it’s a pain it does give a slight increase in case capacity which for this cartridge is not bad thing.

I suppose on that basis, if there is a little more head space on the new bolt, I can overcome in the same way.

 

[25 Sharps]

Dunno about that era of Tikka, but I was informed by a reputable riflesmiths that Tikka bolts were practically interchangeable as the manufacturing tolerances were as little as .001 variance as regards headspacing.
Indeed, whilst troubleshooting an issue, we used three separate T3 bolts, and the fired cases showed no difference in size.

I’ve just tested this theory as a buddy suggested I used a fired case with one, then two layers of electrical tape as a poor man’s no go gauge.

I also have an M590 in .223AI, the bolt closes with some resistance with 1 layer and with 2 layers of electrical tape on the base with quite a bit of resistance, I measured the double tape at 10.5 thou, although it will have compressed in the rifle.

The m590 came before the m595 so may be ever so slightly different, but I think the only real difference was the top of the action being closed on the 595.

I’ll ask the RFD to try the same test on the .222 bolt before I purchase and see what happens.

 

[25 Sharps]

It could if the headspace is excessive wreck your rifle as the gases from the ruptured base of the case blow out into your rifle's magazine well. However that will be found out at proof won't it...if the headspace is so excessive as to allow that. As I am assuming that the rilfe with the new bolt will be sent to proof before it is handed over to you? And if it passes proof whilst the headspace may be longer with the new bolt than it was with the old bolt the gun will be safe.

It won’t be proofed before it is handed to me as I am retaining the rifle and purchasing the bolt alone, on a new bolt slot on my FAC.

I will test as above, if it closes easily on 2 layers of tape I’ll get a gunsmith involved, and the proof house.

 

[Jager SA]

Thanks, for the offer, appreciated .

The thing is, this rifle always had a bit of an excessive headspace issue, which I get over by fireforming cases with a false neck. As much as it’s a pain it does give a slight increase in case capacity which for this cartridge is not bad thing.

I suppose on that basis, if there is a little more head space on the new bolt, I can overcome in the same way.

I have spare .223 gauges if you need them, probably more consistent than a sized case especially when putting quality tape to pack it. Rgds

 

[Donkey Basher]

I’ve just tested this theory as a buddy suggested I used a fired case with one, then two layers of electrical tape as a poor man’s no go gauge.

I also have an M590 in .223AI, the bolt closes with some resistance with 1 layer and with 2 layers of electrical tape on the base with quite a bit of resistance, I measured the double tape at 10.5 thou, although it will have compressed in the rifle.

The m590 came before the m595 so may be ever so slightly different, but I think the only real difference was the top of the action being closed on the 595.

I’ll ask the RFD to try the same test on the .222 bolt before I purchase and see what happens.

Was about to suggest using a fired case & some tape on the head to see if it will close.

 

[6mmarc]

I’ve done this with a Steyr 233 no issues at all
Picked one up with no bolt cheap for spare parts and then decided to try the bolt of my stutzen in it bit tight closing but nothing to scary put 5 into a ragged hole at 50 yards so decided not to strip it just in case I find one with a bust stock or something

 

[Stevie/P]

Looked at a brand new CZ 550 American £450 at garlands great I’ll have it I said then came the fly in the ointment……… we’ve lost the bolt
Same scenario as the OP surprise garlands haven’t tried for a replacement Bolt

 

[25 Sharps]

I have spare .223 gauges if you need them, probably more consistent than a sized case especially when putting quality tape to pack it. Rgds

Thanks, if it’s a long way off a fired case I’ll give you a shout.

 

[25 Sharps]

Just went to the RFD to get the bolt checked with the rifle.

1 tape - stiff to close
2 tape - stops on closing but cammed down with a lot of effort
3 tape - bolt won’t rotate at all.

On that basis I think I will proceed - with the purchase.

 

[HonestJohn]

What’s it like without tape?
What type of tape and how thick?

 

[kenbro]

Hi,
Could you make a case with a false shoulder and work backwards from that until it feel right when closing the bolt, then check that case with how your reloads measure?
Might be talking a load bullocks here though?
cheers, Ken.

 

[25 Sharps]

Hi,
Could you make a case with a false shoulder and work backwards from that until it feel right when closing the bolt, then check that case with how your reloads measure?
Might be talking a load bullocks here though?
cheers, Ken.

Hello mate

That’s how I’ve always formed cases for this rifle think we had a conversation about it when you loaned me the reamer. It’s also exactly how I form .280 brass from .270 as the shoulder has to bump forward something like 15-18 thou.

I have some cases with false shoulders loaded so that will be what I shoot first, and will measure those fireformed cases against some fired with the old bolt to see the difference

 

[25 Sharps]

What’s it like without tape?
What type of tape and how thick?

Closes fine with no tape, I’m using electrical insulation tape.

 

[HonestJohn]

Closes fine with no tape, I’m using electrical insulation tape.

Go no go gauges are always the way to go, no pun intended but if it closes fine without, and slight resistance with very thin tape, you’re probably good. I suspects with a layer of cellotape, you should feel just a tiny bit of resistance on closing, just ‘firming’ as you close the bolt - if so, you ‘should’ be ok - but, do inspect the cases as a precautionary measure

 

[Mr Tree]

When I set my FL die, I occasionally get a variance between sticky bolt & chambers easily,. I put this down to difference between catridge rim thickness. Keep calm & carry on..

 

[25 Sharps]

Variation sorted, (3 days, good old Wiltshire) so went to the RFD today to pick up the bolt amd test the headspace on their tunnel range.

Turns out @Malxwal was right, the headspace for the new bolt was 1.7 thou longer than the old bolt, so still in proof.

The old bolt was cerakoted black to mathch the rifle but I quite like the silver finish. Rifle shoots as well as ever, 9 fireforming rounds on the left hand group and 3 TTSX rounds in the right .