6.5x55 (modern action) Retumbo loads?

Hopkins

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Has anyone had favorable experience with Retumbo in a 6.5x55 Swede modern action. I have a 28" barrel that despises R22. IMRs seem fine so far. I have the Retumbo on hand but no starting point. Other particulars are 139 scenars & 140 A maxs, WLRs and FF Winchester brass.
 

buffybuster

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Re: 6.5x55 (modern action) Retumbo loads?

Retumbo is probably too slow. Unlikely you will be able to put enough powder into the case to get high pressure signs.
 

DocB

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Re: 6.5x55 (modern action) Retumbo loads?

Hopkins,

Second buffybuster. Reloader 25 will probably work better.

HTH,
DocB
 

glock24

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Re: 6.5x55 (modern action) Retumbo loads?

I agree that Retumbo is too slow. Reloader 25 sounds like bad advice as it burns almost as slow as Retumbo, and slower than Reloader 22.

Try a powder that burns a little faster. Start with 43.5g of H4350, 46.5g of H4831, or 50g of N560

Interestingly, the Viht reloading manual shows N560 pushing a 139g Scenar at 3163 fps with a maximum charge weight of 52.5 grains. These charge weights are for modern actions only, and the test barrel was 29"



 

ddavis

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Re: 6.5x55 (modern action) Retumbo loads?

I have some experience with modern 6.5x55's, and also had bad luck with RL22. I got good velocity, but it was too temp. sensitive. Were I in your shoes, I would go with Hodgdon 4831SC. It is one of their extreme powders, so should not be very temp. sensitive, and is close to the burn rate of RL22, which is about ideal for the 6.5x55. I bought a jug of it recently, then sold my x55 and am currently building a Creedmoor.
-Dan
 

dieselten

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Re: 6.5x55 (modern action) Retumbo loads?

I just got a Tikka T3 Sporter in 6.5x55 and started reloading for it. I tried H4350 and H4831SC. I had incredible results with the H4831SC and 140 Amax, 142 Sierra, and 123 Amax. On the 140's I started at 45 grains H4831SC and went up to 50.0 with no pressure signs. My best accuracy with the 140 Amax was at 48.5 and bullets seated .015 off lands. Caution - my rifle has a VERY LONG throat and my bullets are seated way out there (3.150 COAL), which decreases internal case capacity allowing more powder. Lapua brass, CCI BR2 primer, and .002 neck tension.
 

Hopkins

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Re: 6.5x55 (modern action) Retumbo loads?

I had concluded that my next powder would be H4831sc. IMR 4350 and 4831 are doing fine but aren't sweet in the gun. I happened to have the Retumbo and didn't figure it would hurt to ask because somewhere in the past I recall it mentioned in context with 140gr 6.5s. The RL22 so far has been filthy. I am still breaking in the barrel however. It is a Krieger 5R 28" so I am surprised at the carbon fouling with the RL22.
 

Kiwi Greg

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Re: 6.5x55 (modern action) Retumbo loads?

Try some H1000 it works mint in my 260 with 140s although it is a fairly compressed load.
 

Hopkins

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Re: 6.5x55 (modern action) Retumbo loads?

Kiwi, how much barrel do you have on the 260? The H1000 is almost as slow as the Retumbo. I know I have a bit more case capacity than you do.
 

buffybuster

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Re: 6.5x55 (modern action) Retumbo loads?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hopkins</div><div class="ubbcode-body">I had concluded that my next powder would be H4831sc. IMR 4350 and 4831 are doing fine but aren't sweet in the gun. I happened to have the Retumbo and didn't figure it would hurt to ask because somewhere in the past I recall it mentioned in context with 140gr 6.5s. The RL22 so far has been filthy. I am still breaking in the barrel however. It is a Krieger 5R 28" so I am surprised at the carbon fouling with the RL22. </div></div>

If the powder is burning really dirty, that's usually an indication that it's not generating enough pressure. If you can't get enough powder in the case to generate enough pressure to get a clean burn, then the powder is too slow.

My guess is you're probably going to be in the 4350 - 4831 burnrate range.