6mm/22-250 $ SMK 107s

[ptf18]

List; Im shooting SMK 107s with 37gn of AA4350 and Russian primers in WW brass in my 6mm/22-250. Im getting single digits SDs and ESs in the teens but the bolt lift on the fired cases is just abit heavy. The case head shows a very slight "smear" mark of brass although there is NO "indention" from the ejector,Savage action). THe velocity is approx 3100fps. This was at about 50* temperature and Im concerned that as the Texas summer arrives I'll have more "problems".

I backed off the load to a point that there is no bolt lift resistance but the group size, SD and ES falls apart.Im getting velocities in the 2950-3025 area at this point.

Should I leave well enough alone?

I asked at L/R.com about velocitys of the SMK 107s and it seems that the 2950-3000 fps area is where other shooters are running this bullet.

Ive found that seating the bullet .010 off the lead produces the smallest group but Ive only got about .002-.003 neck tension and was told I should try "soft seating " the bullet which I think I could do with this neck tension.

Any ideas? Im getting some what dismayed that I seem to be having such a hard time finding a "good" load for this rifle. Makes me almost want to go back to the .308.

Do you think I'll be burning out the throat sooner if I keep the velocity at 3100 using AA4350?

Lester

 

[reid308]

I'm running the 107's in my 6XC @ 2900 using 39.0 gr IMR 4350
in the 6XC Tubb brass,2'n gen) with the Russian primers & 25" barrel. To me, the 107 seems to really like 2900-2925 in my barrel. It seems to me you are a tad on the warm side with the 6-250 knowing the dif case capacities of the 2. I ran mine up to almost 3000 f/s and the tests @ 600 showed the 2900 was better. YMMV
I run .001 neck tension and soft seat about .015" all my LR ammo
and have found that almost always works best as opposed to jumping the stuff. I never could get a consistant jump as the throat erodes and decieded many years ago to just seat it long and keep up with the throat. Works for me.
Reid

 

[Changeling]

Reid, if you are only going to run the 107's at 2900 fps, why not just use a 6Br/improved case and chamber?
Changeling

 

[reid308]

I shoot XTC and want something that is going to feed well and have a little extra boller room. The 6BR improved or not is working at its maximum level. The 6XC is proven, dies & brass are available. The 6XC has the capacity to push the new 115 gr
bullet to 3000 f/s without strain. It is just a 6 BR 'Long Rifle'. Same front end and same back end, just a little longer.
I don't want a 40 degree shoulder for RF. It has to feed ALWAYS in RF. I looked at the 6-250 but the case taper is not reliable for RF feeding. I know, I know, guys are using it with total reliability and all. I just don't like the steep taper of the case. I have used the 308 for 30+ years and like its shape.
The 6XC is as easy to load for as a 308. No fuss, no bother. Just load to the V you want and the T2K will shoot it into 1/2 moa.
Reid

 

[Changeling]

Reid308, have you tried any primers besides the Russian? Also, have you fired any groups at 600 yards?
Sorry for all the questions.
Changeling

 

[reid308]

I just put a new 30" Lilja 3 grove 6XC barrel on my T2K for Long Range using the new 115's from SSS. I wanted somewhere around 3000 f/s and ended up at 2975 using 39.5 gr H4350 in the 6XC brass, Russian primers. Took it to Butner a week or so back and shot 2 string of 20 rounds ea as F-Class with a Sinclair BiPod and a rear bunny bag. I did this to evaluate the load and the 115's in the new 30". Had a 199-15X and a 200-15X with me shooting the 9 by overdoping the wind. Group uses less than 1/2 the X ring for elevation. I got to trying to shoot the pin out of the spotter and chased the spotter around in the X ring the second string. That opened the group up a bit. Never did hit the pin but I sure scaired it a lot. I have not used any other primer than the Russian for ammo past 300 yds. I tried Rem, Win,
CCI BR and the RWS along with the Russian. The RWS was about 1/2 the SD of the Rem, Win & CCI. The Russian was a bit lower than the RWS. The RWS is a great primer but a tad on the soft side. It will pucker/crater while the Russian just stays flat with any load. Don't try to judge preasure with the Communist Primer. It will lie. Always looks flat and the same until it falls out of the case. Not that any of mine have fallen out.
Reid

 

[Changeling]

Reid308, very well said/compiled! Question was a passing thought that you were able to expound on enough to satisfy all my questions and more.
Has a primer that that tough caused you any problems? What is your firing pin diameter?

Changeling

 

[reid308]

I'm not sure what the firing pin diam is in the T2K? The figure
.066" pops in my mind but that may be in error. Perhaps some more informed viewers will respond. The pin in the T2K has more than enough force to slam any primer I have tried. I have read post of the Russian being a little hard to spark off but I have not experienced a single problem in the 3K+ I have used.
D. Tubb says you must seat them to the bottom of the pocket and the Sinclair Priming tool makes that a snap. I seat them to the bottom and then just a tad more for compression. The Sinclair has the feel for that. Just got through priming 88 cases for the Stars & Bars match this weekend. Gonna push some 115's down 600 yds out of the 30" Lilja @ 2975 f/s.
Reid

 

[AnswerQ1]

I got my 300 cases yesterday. I must say, I was somewhat surprised. They do not appear to have been anealed, and they look somewhat soft. They also have black stains inside the pourous outer finish on many,most) of the cases.

I'm not going to pass jusgement on these cases until I give them a shot though. They could be the cat's ***, and just look like Hornady brass.

 

[jpretle]

I run my 6-250 at about 2950, w/ the 107's. Any more than that causes me problems w/ brass flow.
Win primers, H4350, and win brass. BBL is 27"

 

[Hoier]

Talk about resurrecting an old thread haha