224 80gr Sierra MK in Tikka T3x?

[MichalS]

Dear All,

I have just bought a .223Rem 24" 1:8 twist Tikka T3x Varmint as a budget mid range (300-800m) F Class rifle. I plan on using 80gr SMK as my main bullet. Sierra manual lists recommended COAL as 2,51" - will it be fine in T3x chamber? Do you have any load recommendations?

Thanks in advance,
Michal

[VarmLR]

It is on the edge of what a 1/8 will stabilise but should work ok Michal.  It has a nominal stability factor of 1.49 (Ref:  Litz) so would be happier shot from a 1/7 twist. I think that you would be better advised to try the 77gr Sierra TMK or the 77gr SMK, both of which shoot superbly from a 1/8 twist barrel.

My own load data for the 77gr (TMK) using RS50 single base powder gave excellent results in terms of accuracy and velocity using 23.8gr for 2750 fps and a 5 shot 0.4" group (ES of 11 at 15 thou off the lands or COL of 2.352") and another accuracy node at 23gr for 2650fps and a 0.36" 5 shot group (ES of 3 at 77 thou off the lands or a COL of 2.29").

The 77gr would need much higher velocities (ie 3250 fps) to get it to 1000 above transonic but in the loads above, it would be good to 750 yds and not hammer your barrel as those are moderate loads.

You have a little  more advantage with the 80 smk rather surprisingly over the 77TMK with multi-BC G7 values of .217 (ave) for the 90 and 0.202 (ave) for the 77, but the tmk has the edge over it's non-tipped 77gr stablemate in the smk which only manages an ave' BC of 0.19.

The Lapua Scenar 77gr is also worth considering as this also shoots very well from a 1/8 twist and has a decent .224 cal BC 0f 0.207 G7.

The real performer in the lighter weight match bullets though promises to be the new Nosler RDF 70gr bullet with an impressive 0.211 G7 figure.  I have yet to try these but they should be easily capable of 3000 fps from a 24 to 26 inch tube without getting towards silly high pressures.

[Laurie]

15 minutes ago, VarmLR said:

It is on the edge of what a 1/8 will stabilise but should work ok Michal.  It has a nominal stability factor of 1.49 (Ref:  Litz) so would be happier shot from a 1/7 twist. I think that you would be better advised to try the 77gr Sierra TMK or the 77gr SMK, both of which shoot superbly from a 1/8 twist barrel.

 

The 80gn SMK works just fine in 8-twist barrels. I used to shoot them at modest velocities from a 24-inch barrel straight-pull AR with an 8-twist Lilja at 1,000 yards in the dawn of F-Class when we still used the 2-MOA 5-ring target and the 'V' counted as six points. I'd choose the 80 any day over the 77 for anything beyond 500 yards. Back then, people had trouble believing the 223 would reach 1,000 yards never mind hit anything at that distance. It is far from ideal though with this bullet and in today's club competition standards struggles at 600 yards against a proper FTR rifle or other such long-barrel match rifle whether 223 or 308. Still, you'll have a lot of fun and learn a great deal about wind-doping!

Be very careful on COALs. Sierra's value is based on the Colt AR-15 HBar's chamber that takes the 80gn SMK at 2.550" COAL. It is important to get the bullet seating right for your chamber with this length of bullet.

 

[bradders]

The "Colt" chamber is a 5.56mm chamber and has a OAL with a 80 SMK of around2.550"

The "AMU" chamber OAL with a 80 SMK is 2.500"

A ".223 Wylde" chamber with the same bullet is approx 2.465"

A "Accuracy Speaks" chamber is about 2.450"

A  std ".223 Rem SAAMI" chamber is around 2.420"

There are many other chambers out there, you'll have to measure yours

[MichalS]

1 hour ago, Laurie said:

The 80gn SMK works just fine in 8-twist barrels. [...] It is far from ideal though with this bullet and in today's club competition standards struggles at 600 yards against a proper FTR rifle or other such long-barrel match rifle whether 223 or 308. Still, you'll have a lot of fun and learn a great deal about wind-doping!

Be very careful on COALs. Sierra's value is based on the Colt AR-15 HBar's chamber that takes the 80gn SMK at 2.550" COAL. It is important to get the bullet seating right for your chamber with this length of bullet.

 

Thank You Gentelmen.

As a aging ISSF sport shooter (air and free rifle) my main goal with this project is to learn and have fun. I actually bought a more suitable FTR rifle first (Sabatti Tactical Sport in 308 + Vortex Golden Eagle 15-60x52 scope - I even managed to win a local competition allready),  but decieded having a second "cheap" 223 with budget scope (6-24x50 Vortex Crossfire II) will make for a fun project. I'm completely new to handloading (no such thing in 22LR land :)) so this will be the first attempt for me...  I chose Tikka because it will be easy to sell if I get bored

Regarding COAL - is there a way to check it without measuring? Maybe someone on The forum has a similar rifle? 

 

28 minutes ago, bradders said:

There are many other chambers out there, you'll have to measure yours

The problem is I don't have the equipment to do it

Best regards,

Michal

[bradders]

Yes you do....or if you don't then a Jr hacksaw and cheap caliper will suffice

[VarmLR]

+1

 

the split neck case is an accurate and inexpensive solution.

RE 80 smk...interesting stuff Laurie, thanks for the clarification. Good to know.  

[MichalS]

Thank You again, thats something I'll have to try out.

I noticed the current 80gr SMK has an advertised BC of 0.461 while it was listed as 0.420 a while back.  Do You have any experience of the new vs old bullet?

Also, slightly off topic, can You recommend sensible kit for precision reloading? Maybe there's an article somewhere You can point me to?

M.

[VarmLR]

You may be best advised buying items individually since most kits contain items that you'll end up replacing sooner rather than later anyway.  You haven't mentioned budget, but if I was to start over again, I'd buy the RCBS Rock-Chucker press, Redding dies, Lee factory crimp die, to start with an RCBS or Lyman beam scale, Redding trickler, Lyman case prep centre and the Lee 8/32 threaded case trimmer and lock stud for use with their calibre specific case trimmers (last bits of kit are nice to haves really as you can get by with hand prep tools).  You'll also need comparators.  You'll need them for head-space and bullet seating duties.  Hornady are popular.

If your budget is stretched, the Lee Anniversary kit is where a lot of people start as combined with their pace-setter dies, it's a cheap start.

For case cleaning you can just brush the inside of the cases out, but a lyman turbo tumbler and corn cob media does a good job for little outlay.

[MichalS]

I have measured the max COAL in my T3x using Hornady gauge, and it appears to be 2.38" while Sierra recommends 2.55" for 80gr SMK  Will that be a major problem? One thing I can think of is the case capacity will be lower...

I did some research and found that 80gr Hornady ELD Match has a recommended COAL of 2,39", maybe that would be a better choice in my rifle?