You can make a safe plinker load with that powder, but N-135 is much too fast to be an appropriate powder.
You should be using a powder in the range of 4831. A powder a bit faster than 4895 is ok for making gravel pit plinker ammo, but a waster of a good 140 gr bullet.
Funnily enough I've been getting equally good results with 142 gr match bullets and IMR4064 and IMR4831 in two M96 Swedes.
Back in the day when International was offering their bulk packs of bullets/powder/cases of cartridges loaded with wooden bullets to pull down and reload the powder they sent with the packs was Nobel #44, which was as close to IMR 3031 as it gets. I really liked that powder so bought a bunch of it from Tom Higginson. More than I should have because it bulked up and went bad. The flake powder used for those wooden loads was and still is a great pistol powder for large bores with heavy bullets.
Back to the OP. As Ganderite suggests for most applications N135 is to fast IMHO in the 6.5x55. The thing is, the 6.5x55 was developed in a time when the slower powders we have available today just weren't available. Yes, 4831 type powders have been around for a long time but not in 1895. The earlier powders were also bulkier such as the Rotweil flake types. At the time, when #44 came out it was considered to be fairly slow and less bulky than its predecessors.
I am not surprised that your M38 Swede really likes the quicker powders such as 4895. That powder is an old standby and well noted for its consistency of burn rate. The thing is, it is temperature sensitive. You may find your groups about 4-6 inches lower at two hundred yards in November. The shorter sight radius of the M38 in comparison to the M96 could have some effect as well but from your report on your groups with the faster powder I doubt it.
The fast twist rate allows pressures to build up quickly. Couple that with a long/heavy for caliber bullet and all sorts of changes will occur in that shorter barrel.
As Ganderite says, accuracy within safe pressure limits trumps it all. Many folks think that 4 in groups at 100 yards are perfectly acceptable for hunting medium to large game animals. Well, up to 150 yards they are correct as long as that four minute of angle group prints at point of aim. We all know how easily that can change under different conditions.
One thing the OP really needs to do now that he has established the load with 4895 and now wants to do with N135. He definitely needs to check velocities and trajectory. If you have an adequately long range to do so, you don't need a chronograph to do this. Take a target and shoot it at 100yds then take the same target and shoot it at 200yds and again at 300yds. The point of impact below the point of aim will give you a pretty accurate estimation of your velocity by measuring bullet drop to point of impact from point of aim. Of course, make sure you mark each group at those ranges and from a cold bore.
If the temp dropped to -30, you would see the difference. I doubt it will be cold/hot enough to matter, and in my experience, you shot will more likely be at 50 yards than 150 yards.
The 160 gr bullet is a flat base. If you are going to try 4831 or RL22, try a flat base bullet (in any weight). If your 140s are boat tail, that might be the problem.
I'd contact the powder manufacturer.I'm using imr 4895 in my 6.5x55 Swede. I happen to have a lot of N-135 here. Although burn rates are similar, I can't find any data for this powder with 140 gr bullets. Is there any safe way to work up a load without data?
If the temp dropped to -30, you would see the difference. I doubt it will be cold/hot enough to matter, and in my experience, you shot will more likely be at 50 yards than 150 yards.
The 160 gr bullet is a flat base. If you are going to try 4831 or RL22, try a flat base bullet (in any weight). If your 140s are boat tail, that might be the problem.
Ganderite is right as usual. I do get such temperature swings and more in the areas I hunt. That's why I refuse to work up a hunting load when the temps are over 25C. The difference can mean shooting low at a couple of hundred yards and wounding an animal or shooting underneath it.
That 160 grain bullet is hard to beat under 200 yards and is adequate for any big game in North America. The penetration with that bullet can be phenomenal depending on its construction. I really miss the old bullets with the exposed lead base. I found them to be much more accurate than the cup style we have today which covers the base. Finding 160 grain 6.5 bullets can be extremely difficult at times.
There is no VV in Hodgdon's Reloading Data Center that I've ever seen. I just checked and there is no data for 6.5x55 that uses any VV powders.Go to Hodgdon site they have Vithtavouri load data.
I was thinking the same re: distance. The bullets were flatbased. I don't understand why the rl22 didn't work in this M38. Works great in my other one. I have some of the 160 RN. I expected great things from them but didn't have much success in the M96 or M38. No doubt I was doing something wrong but I don't know what.



























