Accuracy Problems

[winelines]

I know, I know. I must be the only person out there that owns a Sako that doesn't shoot well. Its a 75 stainless/synthetic in .270WSM that I bought a couple of years ago. I have spent a lot of time trying different hunting bullet, powder, primer combinations. I full-length re-size. When I'm trying loads I clean after every 9 shots, and I use both bore cleaner and copper remover. I let the gun cool after every three shots. The best I can do is an average 1 3/4" three shot group. I'll get an occasional good group, but I can't get three consistently good groups out of load. There is a tendency in the groups to string horizontally. I am a very experienced handloader and own plenty of guns that shoot well, so I don't think its me. I have used three different scope, mount combinations with no apparent effect. The trigger is crisp and adjusted to be consistent with my other guns. I have removed the barrel and checked the bedding several times; it seems tight and the barrel is floated back to near the start of the chamber. The only suggestion I got from a 'smith was that I might be getting some slight horizontal movement back at the bedding pin. He recommended a bedding job.

The other thing I discovered is that the freebore is .290 greater than max COL of 2.86 (used 140gr Nosler Accubond for the measurement). I have a couple of Weatherbys and I know they have a long freebore, but I had never heard that as being a Sako characteristic.

So, I will take any suggestions or recommendations, but I was hoping there might be a knowledgeable Sako-person or 'smith out there that could comment on the freebore. Is a long freebore common for a .270WSM Sako? .29 is a lot of jump.

Thanks for any info I receive.

[FortyXDM]

Winelines - I am a Sako owner for over 10 yrs on my current sako, and bought my first back in 72. I am not an expert on them, but do have experience with them and have shot them a lot. I don't think .29 freebore is weird, although a bit long. My 308 gives me the best accuracy at a velocity of slightly over 2600 fps with the ogive .11 from the lands.
If you were to hand me your rifle and tell me "find the best loads with the path of least resistance", here is what I might do.

1)Shoot a few different factory loads first. Record vel of my chrony. Shoot just one type, if that is all you have.

2) Call hodgden powder and ask them what they hear has given good accuracy results in that round for both IMR and Hogden powders. (start there, and you can branch out to other powders later.)

3) Build some loads starting in the middle and working up 2/10 gr at a time. Use factory oal for all. If you find a powder charge/velocity that seems to be the best, then stop there for now. This load "most" likely will be around 90 per cent of a max load. (probably)

4) Using that powder charge, load 3 rounds @ at several seatings using an ogive add on to your calipers to give you the true ogive length measurement. Start at say .25 to lands for first 3, then .22 for next three and .18, then .15 then .12. As you get to the sweet spot, groups should begin to show improvement.

5) Do this with several powders ( I know it takes time)

I have been lucky in that mine shot good with factory Fed match right out of the box and was often under 1 in with my first handloads. ( I did have a good idea where to start) The real improvement in consistency came with a change in bullet seating.
In case you are wondering, my gun I consider an under 1 in gun. I have had many 3 and some 5 shot groups under 1/2 in , but I can't promise anyone that I can shoot that tomorrow. It is not a precision bench arm and never will be. It is a very accurate hunting rifle. If the very best shooters took it to a competition as it is now outfitted, they wouldn't even qualify. One hole guns cost a lot of time and $$.

Its late, so if I am unclear here, don't hesitate to ask me for clarification. Ha.

Tom

[winelines]

Thanks for the reply FortyXDM.

I followed your process almost to the letter.

1. First shot three factories - Fed 140 Accumark (best group <2"); Fed 130 Bal Tip, Rem 130gr Sirocco. Recorded all velocities.
2. Went to other web sites to get recommendations from other .270 WSM shooters. Tried MagPro (most recommendations), 7828, IMR 4350, HSC4831 and RL22. Combined these with Fed mag, CCI mag and CCI BR primers. Combined these with Nosler Accubond, Partition, Bal Tip, Barnes tsx and a couple of other bullets in 130 and 140 gr. Chrono-ed all loads.
3. Built the loads starting in the middle and moving up .5gr each time to max. Best load was 140 Accubond, CCI BR primer, HSC4831 powder (about .5gr below max) Gave reasonable velocity (150 fps below MagPro and Fact best).
4. I don't think you understand the freebore issue. My measured freebore is .29 in at Max overall cartridge length. The only thing I can do is increase the freebore by seating the bullet deeper. I could shorten the freebore slightly (.06) by going above COL recommendation, but I quickly run into the clip length limit.
5. See #2

I think I did everything by the numbers; it did take 1 1/2 years. But I haven't been able to improve on my first factory trial.

I guess my next step is to try a bedding job, and/or return it to the factory.

I still find the freebore issue curious.

Thanks again for your thoughtful response.

[SwedeSteve]

I think .29 freebore is curious as well. I would contact Sako and see if this a defect.

[FortyXDM]

Wine - If .29 is "actuall" jump from ogive to lands, I was suggesting shortening that by moving bullet out. However, if clip issues come into play you could have a problem. I agree with Swedesteve that this sounds a bit to "free". I also assume you are using ogive measurements rather than overall cartridge length. (to tip). Something is obviously not right. I would take it to a competent smith and see if they can reset the barrel after trimming by say 10 thousandths or so. They can advise you better. They may want to inspect the throat/barrel with a scope device.
You could also contact Sako, but that might take a bit of time. It could be that one slipped through, (doubtful as they test each gun) or that something "happened" with the first owner and that is why it was up for sale. It does happen. Good news is that it should be correctible. The gun should shoot to moa under proper conditions with proper loads. (on most days - ha)
Let us know what happens ...please.

Tom

[15AcreWoods]

Originally Posted by FortyXDM

Winelines - I am a Sako owner for over 10 yrs on my current sako, and bought my first back in 72. I am not an expert on them, but do have experience with them and have shot them a lot. I don't think .29 freebore is weird, although a bit long. My 308 gives me the best accuracy at a velocity of slightly over 2600 fps with the ogive .11 from the lands.
If you were to hand me your rifle and tell me "find the best loads with the path of least resistance", here is what I might do.

1)Shoot a few different factory loads first. Record vel of my chrony. Shoot just one type, if that is all you have.

2) Call hodgden powder and ask them what they hear has given good accuracy results in that round for both IMR and Hogden powders. (start there, and you can branch out to other powders later.)

3) Build some loads starting in the middle and working up 2/10 gr at a time. Use factory oal for all. If you find a powder charge/velocity that seems to be the best, then stop there for now. This load "most" likely will be around 90 per cent of a max load. (probably)

4) Using that powder charge, load 3 rounds @ at several seatings using an ogive add on to your calipers to give you the true ogive length measurement. Start at say .25 to lands for first 3, then .22 for next three and .18, then .15 then .12. As you get to the sweet spot, groups should begin to show improvement.

5) Do this with several powders ( I know it takes time)

I have been lucky in that mine shot good with factory Fed match right out of the box and was often under 1 in with my first handloads. ( I did have a good idea where to start) The real improvement in consistency came with a change in bullet seating.
In case you are wondering, my gun I consider an under 1 in gun. I have had many 3 and some 5 shot groups under 1/2 in , but I can't promise anyone that I can shoot that tomorrow. It is not a precision bench arm and never will be. It is a very accurate hunting rifle. If the very best shooters took it to a competition as it is now outfitted, they wouldn't even qualify. One hole guns cost a lot of time and $$.

Its late, so if I am unclear here, don't hesitate to ask me for clarification. Ha.

Tom

I agree with all the above. I had a rifle once that was not consistent. I tried everything above, no improvement. I was finally told my barrel might be fouled. I said No it was shined with a bore scope but I plugged the barrel and filled it with copper solvent, left it two days and when I ran a tight patch thru it, the patch came out green. I did it twice more until the patch came out white and no more problems. I don't know why I could not see the fouling but it was there.

[Deersniper]

Sounds like a factory return if the bore is not fouled. My 300.00 Stevens got 3/8 groups at 100 yds this weekend in 20 MPH winds.

[ArkansasHunter]

Go buy you one of these and see if it helps. I've got one on one of my rifles and it greatly helped the groups...A.H

[tappedandtagged]

^The gunsmith at my gunshop swears by these.

[winelines]

Thanks for the inputs guys.

I have just been using the ammonia based copper solvent. I'll try the heavy duty approach.

Re contacting the factory: Sako gives no contact info on their web site - neither phone nor email. In fact, they tell you not to contact them but to contact Beretta. And Beretta doesn't give you any customer service contact on their web site. I suspect I'll be able to dig one up if I try a little. I am curious about the freebore.

Thanks for the de-resonator idea. I hadn't considered that since I thought it was aimed at non-reloaders. Theoretically, a reloader should be able to vary the bullet/powder/primer to change the natural frequency of the barrel after ignition.

Thanks again for all your comments. They were very helpful.

[ryansparky1]

Originally Posted by Deersniper

Sounds like a factory return if the bore is not fouled. My 300.00 Stevens got 3/8 groups at 100 yds this weekend in 20 MPH winds.

I think you mean 38 inch groups.

[ArkansasHunter]

Tapp you'll get heckled by some here but they work where I live and they look kinda cool on your rifle too !!!...A.H

[FortyXDM]

Originally Posted by ryansparky1

I think you mean 38 inch groups.

20 mph, wow. Sounded windy to me.

[SwedeSteve]

Winelines- Beretta U.S.A. Corp 17601 Beretta Drive Accokeek, MD 20607, USA Telephone 301-283-2191. Gallery New York 718 Madison Avenue New York, NY 10065, U.S.A. ...

[winelines]

SwedeSteve,

Thanks for the info

Jack