Fox Tales

On 12/14/2020 at 4:52 PM, gunner said:

Nice mini mauser action, i though my 527 was a bargain 220 : (  what make is the rail ?  id prefer this to say a factory tikka t3 . Nice looking rifle . simon6ppc on tube uses the tmk in his 223 sako with great affect. Think he's the same guy on here with same name . Good luck with development i hope its a tack driver. 

 The rail is a Britannia , 10 moa . ( Off the top of my head about £85)

Looking forward to the load development , I've an OBS follower coming in case the TMKs need to be closer to the lands than max mag length will allow . All good fun .

 I'll check out the tube. 

 Cheers

1 hour ago, baldie said:

You should have sent that rail in with it. If you want it doing, give it Steve, he's down every week, and i'll do it with other stuff, no charge.

 Cheer Dave , your a gent . I wasn't sure if  it would go  back on the dovetails without damaging thee finish ,  if I'm honest  . 

 It pleases me no end . 👍. 

9 hours ago, Sherlock said:

Lovely rifle - I'm sure it will be a tack driver without the cost of a full custom rifle.

what weight bullets are you planning on shooting

Cheers ,

 I had 69 grain TMK's in mind when I chose the barrel ,  just loaded some to start development . Fingers crossed for some reasonable weather .

 FT

Big shout out to Steve Kershaw for all the smithing and Dave Wylde for the excellent Cerakoteing .

 I bought this originally for the action , purely with a build in mind as funds permitted . £75 saw me take possession of a shot out CZ527 , bargain ! 

 Barrel  - 1 in 9 twist , 22" Sassen , Remington sporter profile. 

 Bolt with extended handle ,

 Trigger - Timney (for the CZ550 , not magnum ) set at 1 1/2 lb ,

  Stock - Form Carro in ebony ,supplied by Davey and Son  , pillars and devcon bedding .

  Cerakote by Dave,  compliments the build perfectly and the finish is flawless. 

 I know I could have bought factory and this isn't the most exotic build but who cares . 

Please PM me the price and available top disks . Interested in 223 , 243 , 6cm

 Regards,

    FT

 I had excellent results with RS62 ,  Rem 9 1/2 primers and the 87grain Vmax. 

 Like onehole, only a 5 thou jump .

On 11/17/2019 at 11:34 PM, gunner said:

Ha , looks like the Royal color laminate - i went for a barracuda / boyds in Royal laminate  subtle,  or is yours grey black ? Hard to tell by the pikky 

 Yeh , just the black /grey. I really wanted a grs but funds were running low . 

 I've only put the first 5 rounds though , cleaned between each . Hopefully a little more breaking in at the weekend. 

 The stock is nothing more than a Boyds thumbhole, nothing really special. 

 I also had Steve fit a Timney trigger, which has adjusted nicely to 1 1/2 lb .

 If the weather stays clear , it's play time !

 Yeh , I don't know how to upload multiple pictures. 

 Just collected my 527 223 from Steve Kershaw  . He kindly fitted a tactical bolt handle at my request whilst rebarrelling . Steve had to first make a mandrel to enable turning. 

Check out the fit and scope clearance . The scope has a 43mm ocular and a pard bayonet fitting installed. 

 Thanks Laurie,  I was using 10thou for ease rather than accuracy. After reading your reply I can see it would have little to no effect, especially when variation of Ogive shape is taken into consideration.

 I doubt I would see a difference of 3 thou in seating down range . 

 Cheers 

 I may have put my point across poorly .Apologies .

 Using a headspace gauge measure a new case (head to datum point on the shoulder ). Now if we subtract this figure from the COAL we will get a figure that relates the  shoulder to bullet . If we then apply the same to a neck only sized , fire formed case and load to the same COAL the relationship between shoulder and bullet will be shorter by comparison. 

 Since the shoulder forms the stop during the firing sequence this means the bullet is further from the lands . Admittedly if you always FL or only do load development after fire forming and NS then this relationship will always be constant. 

 Which brings me to the question of why we don't measure seating depth in relation to the shoulder ,rather than OAL ? 

Yes I know I'm probably over thinking this , sometimes it's just good to question conventional wisdom. 

 Just putting it out there.

 As for measuring I like to measure to Ogive and use a bullet of average length after measuring a dozen or so from the box . Whichever method is used the relationship will change .

 The standard method to calculate seating depth , would be to first measure the max OAL to the lands , using a OAL gauge. We can then apply this measurement to calculate bullet jump .All pretty standard stuff , I know. 

 Supposing we make the initial measurement using a SAMMI spec case and apply to new brass . Following load development we arrive at jump of 10thou' for best accuracy. All's good so far .

 Now we take a different tack and decide to neck size only. We know that the cases have gained length and it's measurable using a headspace gauge. If the case has gained 10thou' then the bullet seating has proportionately changed and the jump increased. The reason behind this is that during the mechanics of the firing cycle the case is pushed forward in the chamber and using the shoulders as a stop .

Applying this should we increase COAL to accommodate and if this is the case would calculating shoulder to tip length be of more use ?If this is the case then seating dies are fundamentally flawed and seating should be in relation to the shoulder .

 Comments please .

 Cheers

 Has anyone experience of the above? 

Cheers 

 Rangefinder , 

I suspect it will require a 1 in 8 twist to stabilise .

 You could check by entering the bullet details into a twist calculator  (JBM) .

Length = 32.03 mm

Diameter =6.17 mm

Weight=6.67 grams 

G7=0.258

 As Snakeman pointed out you may well be at the barrels limit at the 85 to 95 grain bullets. Especially if they're the slippery sort .

 In reply to the OP's original entry , I noted a big difference in velocity and pressure signs between my 1st and 2nd tubs of RS62 .

 The same charge weight in my 243 using 87grain Vmax saw a drop in average velocity of 187 fps using the second tub . ( Quite clearly not of the same batch , different containers and a year between purchase. ) This equated to 0.1 grains equalling 31 fps , the velocity confirmed by my chronograph appeared quite linear. I'm sure others must have noticed this !

 I'm not a QL user myself  , but is it possible that QL's data was based on the earlier production runs ?