Does Retumbo = Recoil ?

[AlexF]

Hi, I had big recoil issues with a 270 WSM load which used a case full of Retumbo to drive a 165gr VLD at 2900fps.
I did a very interesting experiment: I loaded a 243 Win 105gr 6mm A-Max at around 2700-2800fps using Varget, H4831 and Retumbo. My 243 Win has a 22" barrel (my 270 WSM has a 24" barrel)

The results:
Varget recoil was minimal
H4831 recoil was minimal
Retumbo recoil was much bigger, including barrel jumping and a huge muzzle blast!

This is exactly what I experimented with my 270 WSM only on a larger scale. I guess that Retumbo needs a long 27-30" barrel and that barrel pressure is very high at the muzzle.

I'd like to know if someone had a similar experience with slow burning powders,
Alex

 

[prosper]

the mass of the powder used adds considerably to recoil. This is why muzzle brakes are effective - the recoil caused by the mass of the powder is re-directed.

So, all else being equal, the load with more powder will recoil more.

 

[GRiNGo]

You know we found that RL-15 seemed to recoil less than powders with equivalent amounts. Not sure why but seemed to be to a number of us.

 

[CanuckWR]

270wsm is a bigger bullet moving faster, more energy used to propel the larger mass equals more recoil energy.

270wsm kick pretty hard in a sporter weight rifle as it is.

 

[sunray]

Retumbo uses more powder at slightly higher pressures than H4831 in .243. Varget's pressures are higher.
Considerably more Retumbo in a .270 WSM with 160's. (Five grains doesn't make much difference.) However, H4831 is at higher pressures with slightly lower velocity.
So it isn't the powder. Most likely the weight of the rifle and/or the contour of the barrel.

 

[Dogleg]

Heavy charges of slow burning powder gain their velocity by pushing the bullet longer and harder resulting in more speed on the bullet.

Because of the annoying equal and opposite thing, it also pushes the rifle longer and harder resulting in a harder longer push to your shoulder. You can also add half of the increased powder weight and add to the bullet weight for the calculation if you want.

Sometimes the difference can be considerable. An example is the .300 Win. Load it up with H4350 and you'll get nominal speeds and creampuff recoil. Stoke it up a case full of H1000 for a bit more speed, and it can get somewhat rude. It's almost like a different caliber.

 

[Obtunded]

Dogleg nailed it. It is about its burning speed, and retumbo is near the bottom of the heap. Google powder burn chart and it will show you.