Multi Radial Rifling MRR ans non lead ammo

Squiresiv

Member
I have a Sabatti 6.5 x 55 SE that has MRR - I have tried Hornady factory ammo (non lead) as well as 120gr and 140gr non lead heads from different manufacturers, 3 ladder loads so far and all rounds fail to stabilise, hitting target almost side on and nothing you'd call a group. I've also tried mod on and mod off and two different types of powder.

With my Sierra 140gr lead rounds all is fine.

Has anyone else had issues with MRR in switching from lead to non-lead?
 

Steff

Well-Known Member
This is not a matter of lead or non-lead. It's a matter of bullet lenght. A 140gn non-lead is probably too long for the barrel twist. Try some more 120 gn bullets form other manufactures than Hornady. And give the barrel a good clean including decoppering. BTW MMR was especially developed with an eye on non-lead projectiles.
 

Squiresiv

Member
Hi Rider, thanks for your response. The Hornady 140gr head is a long one and nearly 8mm longer than my lead Sierra Gamekings, hence loading to a longer COL of 3.0"
I've tried the Neilson Sonic Hunter in 120gr (5mm longer than the Sierras) which is a turned brass bullet head, but that failed to stabilise either. I have a 1:8 twist rate and was interested to read your comment re MRR being developed with an eye on non-lead projectiles.
I have a friend trying the Hornady 120gr GMX heads so will get a couple off him and load up a few to see what happens.
Thanks for the cleaning advice too, I'll feed back when I have any results.....good or bad
 

Squiresiv

Member
Thanks for all the help and advice, all sorted. Looks like the key is to go light for calibre with the non-lead bullet heads and load them deep as they like a jump to the lands. I used Hornady 120gr GMX with Reloader 22 - 46.5gr and a COL 2.933" or 2.309 to the ogive. This gave an average speed of 2800 and a very accurate group. (I also tried Ramshot Hunter with very similar results and a friend has tried N160 with good results)
Of course individual guns like different loads and it may need tweaking for you but it's good for me.
One happy hunter
 
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