Sako throat length?

[Tesoro]

I have a new to me Sako A1 L461 in 223. I got my hands on some sierra 55gr bthp and H322 powder. The first thing I did was to find the lands by loading a blank casing and painting the bullet with a sharpie. Surprisingly in order to reach the lands the coal was way out of spec to fit in the magazine so I didnt bother with the typical 30 tho jump starting point or use my comparator! I made up some test loads and the bullet is seated to the neck base, which is how I like them for field loads. Tension is around 3 thou using before and after neck od measurement. Havent test shot any yet due to weather.

And then I took a 70gr speer sp ( for my 223 AR 1:8 deer load) and in-order to reach the lands it was 10 tho short of max 2.26in coal to fit in mag. Just used the 70gr to see the fit out of curiosity.

So, unless I am all wet, it appears my L461 has a much longer throat than one would expect to see in a chamber made for a 1:12 twist 40-55gr. Obviously a long bullet jump dosent seem to affect accuracy but just curious. Comments?

 

[SeabeeKen]

They certainly didn't take into account the mag length and a 12 twist in this day and age seems a waste

 

[243winxb]

bullet is seated to the neck base,

Same here. Not to worried about a factory chamber. Bullets seated long, nose first, then chambered.

 

[Tesoro]

They certainly didn't take into account the mag length and a 12 twist in this day and age seems a waste

Depends what u are shooring at. Cant have the best of both worlds with one twist

 

[SeabeeKen]

Depends what u are shooring at. Cant have the best of both worlds with one twist

My 8 twist rifles shoot great no matter what I stuff in them but one has such a short mag it has to jump .1" or be fed by hand

 

[dgeesaman]

I have a new to me Sako A1 L461 in 223. I got my hands on some sierra 55gr bthp and H322 powder. The first thing I did was to find the lands by loading a blank casing and painting the bullet with a sharpie. Surprisingly in order to reach the lands the coal was way out of spec to fit in the magazine so I didnt bother with the typical 30 tho jump starting point or use my comparator! I made up some test loads and the bullet is seated to the neck base, which is how I like them for field loads. Tension is around 3 thou using before and after neck od measurement. Havent test shot any yet due to weather.

And then I took a 70gr speer sp ( for my 223 AR 1:8 deer load) and in-order to reach the lands it was 10 tho short of max 2.26in coal to fit in mag. Just used the 70gr to see the fit out of curiosity.

So, unless I am all wet, it appears my L461 has a much longer throat than one would expect to see in a chamber made for a 1:12 twist 40-55gr. Obviously a long bullet jump dosent seem to affect accuracy but just curious. Comments?

I had one of those rifles last year and contact with the lands was not possible. I got good groups using Barts and Berger 52gr.

My Sako 6PPCs of the same time period are the same way - I can only reach the lands using certain 70gr bullets just barely engaging the neck. It occasionally shoots well that way but I don’t waste much time trying to build a tune on that.

 

[Tesoro]

Well just shows that there is more to things than bullet jump!

 

[Laurie]

Surprisingly

Not to me. As others say, throat wear intrudes, BUT what a manufacturer puts in his chamber on the factory line and what the SAAMI spec drawing shows are more often than not two very different things indeed, even with a quality rifle like the L461.

 

[Dusty Stevens]

Make em as long as you can then start jumping them farther to find your load- only one way to go. They dont have to touch the lands to be a good load ive seen jumps over .125 shoot just fine

 

[Tesoro]

And make straight ammo!

 

[Capt. Oblivious]

I jumped 87gr VLD's in my 243 A series over .15 and they shot just fine

 

[COLT45SA]

I had one of those rifles last year and contact with the lands was not possible. I got good groups using Barts and Berger 52gr.

My Sako 6PPCs of the same time period are the same way - I can only reach the lands using certain 70gr bullets just barely engaging the neck. It occasionally shoots well that way but I don’t waste much time trying to build a tune on that.

I had a very accurate SAKO Vixen Hunter with some factory loads. My reloads were with a 68gr Nosler. SAKO's factory loads used a 70gr bullet. I still have 2 boxes of the original factory loads. I'm certain that when SAKO designed their chambers for the 6mm PPC-USA cartridge they used a chamber depth with that bullet weight in mind and including some latitude for varying ogives by different bullet manufacturers

 

[NorCalMikie]

One size chamber length fits all when lawyers get involved. That's why I have ALL my barrel chambers cut to MY SPECS. That way, nobody to blame but me.

 

[Laurie]

One size chamber length fits all when lawyers get involved.

To be fair to manufacturers, the sheer numbers and varieties of 224 bullets now available even when limited to the 60gn and below class for 12-inch twists, calls for Solomonesque type judgements.

The other factor too is that few if any put a true SAAMI 223 Rem spec chamber into 223s with its minimal (25 thou') freebore, especially with the increasingly common adoption of faster twist barrels. These manufacturers know that no matter how often they say that only 223 Rem spec ammo should be fired in their rifles, that many American owners in particular are going to put SS109/M855 spec 5.56 Nato cartridges down the barrel.

In reality, there should now be a second '223' factory and SAAMI spec these days using something like the Wylde chamber form and specified for factory rifles with 9-inch or faster twist barrels.