Sierra 183gn

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ajvanwyk
Posts: 440
Joined: Tue May 17, 2016 5:50 pm

Sierra 183gn

#1 Postby ajvanwyk » Mon Feb 19, 2018 2:29 pm

Has anyone noticed the Sierra's getting fatter ? This may have been covered in other posts (although I couldn't find the info).

I've been shooting an older batch of Sierra's that measured +- 0.2836. The most recent lot measured .2840 on the nose. Is it just me ?

Albert
Albert
Rosedale Rifle Club
Australian Points Series

williada
Posts: 969
Joined: Wed Jul 22, 2009 12:37 am

Re: Sierra 183gn

#2 Postby williada » Mon Feb 19, 2018 5:39 pm

Albert, assuming your measurements are correct and you have warmed up the measuring device and projectiles then I can tell you that from past experience with project Penumbra in 2000's the Winchester factory received projectiles from Sierra produced from different machines. If my memory serves me well it was 4 machines. As such the dimensions were slightly different depending on what batch was used from each machine. Peter Pearce and I visitied Winchester to consult with them in regards to the production of Palma ammo to be taken to England. Herb McRorie, Ray Parker and Max Hedges then further hand sorted that ammo, sixteen thousand rounds for the Poms to shoot a record score with in the Australia match.

You can expect projectiles to vary with batches as the dies wear. Depends on when they are replaced. Its important therefore to buy sufficient to last the competitive life of a new barrel at an elite level. Of course there is the relationship with bore size for more efficient gas seal, assuming the jacket hardness is pretty uniform between batches.

Audax
Posts: 38
Joined: Wed Sep 27, 2017 8:48 am

Re: Sierra 183gn

#3 Postby Audax » Tue Feb 20, 2018 5:31 am

Yes Albert and Williada...the SMK 183gr are the smallest of any. I had some that would not shoot well in some barrels and suspect the diameter was the cause being 0.2839". Sierra when queried responded that size is at the bottom end of their manufacturing tolerance range so it is surprising smaller diameters exist.

If they are producing erratic results Sierra would be keen to know I am sure.

Lapua historically have been the largest at 0.2844", Berger and ELD-M 0.2842"...be interesting to see what develops at Berger now that Nammo are in charge


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