IMR 4320 and the 6.5x55 round

[milsurp2.0]

Anyone else use IMR 4320? I've reloaded for years with it in the 8mm mauser and the 7.7 Arisaka and never had a problem. Recently got a M96 swede and loaded up 3 rounds with 39 grains of 4320 under a 139 grain soft point and had severe sticky bolt. Primers were flatter than I cared for. I checked headspace and checked for lug set back. Seems the IMR 4320 is prone to pressure spikes in bullets with a lot of surface area. I've looked around on the net and found a few instances of other people experiencing these pressure spikes. Strange. Just thought I would pass this on even though 4320 seems to be going the way of the dodo bird.

http://forums.gunbroker.com/topic.asp?TOPIC_ID=318262

I bought 8 LBs of IMR4320 a few years back and called Sierra concerning loads.
The first thing he told me was one of the staff just blew up a 96 Swede with IMR 4320 using the starting load.
No BS, I recommend what Sierra recommended.
Do not use IMR4320 in a 6.5 Swede load.

That does not mean it is not useful in other calibers however, I sold the powder as it seems sensitive and unforgiving when its boundaries are approached where as powders like 4895 are so forgiving.

IMO (and Sierra's)

 

[flatwins]

As much as I love the 6.5x55 (got another Swede on the way) I have not reloaded for it yet so I don't have any input on powders. MoBoost is very familiar with reloading for the Swede so I suspect he'll be along to offer his input. I do know that Reloader 22 was\is popular for the Swede and I have a pound of it around here for that purpose.