Sierra 183's

[falconpilot]

Just thought I'd show my results with the new Sierra 183's. This is my second time to the range with them. Using suggestions from another user, I seated them at zero touch. First trip to range, I shot 5 groups at 600 yards..51.5, 51.7, 51.9, 52.3, and 52.5 of H4350. Was mainly looking for velocities and nodes. Groups ranged in 2-3.5" range shoot in heavy mirage. Velocities started at 2800 and went up to 2880 with 52.3 grs where I started getting a slight click on bolt lift so I didn't shoot the 52.5 load. Went back to range today in fair, but cold conditions(45F). Since 51.7-51.9 showed best groups and velocities where I wanted(2830-2850 range), I loaded 5 rounds of each for today. The 51.7 shoot around 2 1/2" with little vertical. The 51.9 load is shown below, my best ever 600 yard group.

The 183's are going to be winners. Rifle is my new SOP, straight 284 with 320neck, .215 fb, virgin Norma 284 brass. BAT M, Kreiger 1:8:5 32".

 

[Drop Port]

That's good to hear, I hope to build some kind of 7mm in the future and want to run a 180 class bullet. It's always nice to have another bullet option. What kind of ogive do they have? Nice shooting! looks like good things to come.

 

[Firefighter]

That's a head turner,,,congratulations on your best group and beautiful gun!!

 

[tonyb]

Good to see. I have a box awaiting my .28 Nosler build if I ever get around to putting it together... Awesome group, and beautiful rifle!

Tony.

 

[fastarget]

Nice shooting. How. Do they work with slower twists? Anyone try them with 1/9?

I ran these through the twist calc. Says 1/8....but you never know

 

[Scott Harris]

looking great Jim. I sorted a box and the uniformity looked excellent....not shot them yet.

 

[falconpilot]

I'm not sure that a 9 twist will stabilize them out at 1000 and beyond..Sierra says 1:8 twist, but it looks like the 8:5 will work fine..I think Sierra likes being on conservative side with their twist recommendation.

Scott....After sorting through about 250 of them, 3 thousands was the biggest spread I could find..threw them all back together and will just shoot them, no need sorting...better things to do with mine time IMO.

As a side note, I believe Sierra's BC to be correct. The 183's need 1/2 min of wind less than the hybrids at the same velocities.

 

[Dusty Stevens]

32" huh?

 

[falconpilot]

The barrel stretcher of yours works I guess..that or wrong barrel!

 

[avidflyer]

Nice groups, what primers did you settle on?

 

[falconpilot]

BR2's..

 

[Sheldon N]

I'm not sure that a 9 twist will stabilize them out at 1000 and beyond..Sierra says 1:8 twist, but it looks like the 8:5 will work fine..I think Sierra likes being on conservative side with their twist recommendation.

What did you measure the bullet length of the 183 at? Can't find the spec online anywhere and wanted to run it through Bergers twist calculator for my shooting conditions.

 

[tclaunch]

Now I know why I have a young mans 8.5" twist Krieger here and he is climbing the walls for me to get done !!!

 

[falconpilot]

Bullet length base to tip measure 1.595-1.600. As stated above, the base to ogive measurement stay with 2 to 3 thousand total spread.

 

[rickiesrevenge]

Nice shooting!

 

[kyreloader]

Falconpilot, can you define zero touch?

Not sure I have heard that nomenclature. I will be testing soon, when I get my barrel back (thanks Tim).

Thanks in advance!

 

[falconpilot]

http://forum.accurateshooter.com/threads/finding-the-lands.3892416/#post-36689601

Guess I should have just called it my Zero. Not into the lands..guess I'd really be jumping the bullet 1 thous.

 

[johnnyi]

Amazing results Jim...Beautiful rifle!

 

[Laurie]

Bullet length base to tip measure 1.595-1.600. As stated above, the base to ogive measurement stay with 2 to 3 thousand total spread.

At 1.6" OAL, the Miller Rules calculator says 1 in 8.3" needed with 2,825 fps for a full 1.5 Sg value as now being recommended. 1 in 8.5" is probably close enough at 1.45 to hardly worry about under 'standard' conditions, and that rises to 1.5 and above for those doing their shooting at higher altitudes / lower atmospheric pressures and in warmer air. The commonly used 9" twist's Sg value would be a calculated 1.30 in standard conditions, enough to 'work' but reducing the actual BC.

I have a Bartlein gain-twist 8.5 to 8 twist barrel on a straight 284 that shoots the older 180gn SMK well. The new 183 looks worth trying when it eventually reaches GB.

 

[Sheldon N]

Thanks, looks like I need an 8.5 twist at least for my conditions.