Just Bought a New Stihl MS-391. Help me ID the chain model# please (and other questions)

I used this model (MS-391) for years when I worked in maintenance at a local college. I grew to love it. I just bought a new one for myself. I had to travel out of town to get this model because my local dealer had it on backorder for longer than I'm willing to wait. But I'll keep my service with my local shop.

The bar is a 20" Rollomatic Super E (aka ES) #3003 000 9421. Stihl's chain guide doesn't have this bar on it. Can someone give me the model number of this chain? I just bucked some green red oak and sweet gum, and this is the chain I want to stick with. It's aggression I remember.

Also (and this one's a stupid question, so feel free to mock me): I use ethanol-free gas and I mix my chainsaw fuel in a 1 gallon container. I accidentally purchased the mix for 2 gallon (5.2 oz). Is there anything wrong with just pouring half (~2.6 oz.) the container in the 1 gallon tank? I measured in a measuring cup, so it's not precise, but it's very close.



 

Nealm66

Feeling the Heat
Sep 25, 2020
264
Western Washington
I would be fine with the mix ratio, not sure what you mean by chain model #. It appears to be full comp chisel bit 3/8’s for a stihl 20” bar. Hope that helps
 

Nealm66

Feeling the Heat
Sep 25, 2020
264
Western Washington
There were some guys running it when I was cutting in Idaho for Columbia helicopters, everything had to be limbed and they claimed it helped a lot for that. There were quite a few of those guys that didn’t have a grinder though
 

Nealm66

Feeling the Heat
Sep 25, 2020
264
Western Washington
It could be semi skip now that I get a better look. I run full skip so it looks like a lot of sharpening to me ha ha. Main thing is it’s 3/8’s chisel bit 63 gauge. If you use a raker gauge and do a good job sharpening, it won’t make much difference in speed but will feel smoother in a hard wood
 

RockyMtnGriz

Member
Apr 19, 2019
87
SW Montana
The chain shouldn't be hard. It's clearly a semi chisel, unless the picture or my eyes are really fooling me. Easy for you to look and confirm: Does the cutter look like a ? or a 7. If it's a semi chisel, the cutter will look like a ? and it won't have a real definite point at the curve of the ?. The transition from the top to the side of the cutter will be a rounded profile. If it's a full chisel, the cutter will look like a 7, and there will be a long point at the angle of the 7. The angle between the top of the cutter, and the side of the cutter will be a sharp 90 degrees.

What you have is clearly a standard chain. No illusions possible there. It's not a full or semi skip.

With the cutter style determined, from the picture provided, it's 3/8 pitch, 72 driver, 0.063 gauge, no skip. With that info, you can select the proper box at the store, or find the part number to order on any of the chain manufacturer's websites.

If ordering online, you'll need to know, but if you're going to your local saw saw shop, just take the chain with you and hand it to them.

If you don't bore cut, buck logs longer than your bar much, or just don't want to get hit by the bar of your saw, consider a green coded chain. A real kickback incident is far more frightening than most people would believe. I've been running saws for 40 years, been trained and paid to run a saw, and thought I knew what that was all about - until I actually had my first real incident a few years ago. I use green chain as a first choice now. Yellow when I have a need for it. I'm in a small minority here, I know.

FWIW - a full chisel usually cuts faster in most wood, and dulls much easier. It also usually isn't as smooth cutting, and tends to kick more. If you're cutting dirty or huge wood where you have to tease cutting dirt to buck it, or just hit dirt as a matter of style, you probably wouldn't like it. I actually prefer semi chisel, like your stock chain for my softwood. Kicks less, smoother, stays sharp for a looong time if kept away from the dirt. doesn't flat quit if it gets a little dirt, lasts a lot longer, and isn't much slower in my wood. But so many people are into the max cutting speed of full chisel, that it can be a little harder to get, and you'll have to make sure that your dealer doesn't give you full chisel by default.

If you're using a measuring cup to mix your fuel, you're way ahead of most of the population! Good to go!

If it helps someone, I buy Chevron/Texaco/Conoco 2 cycle oil by the case(s), and use a repurposed quart StaBil bottle with the measuring chamber to meter it out. The StaBil bottle checks out against a shot glass, and the oil is far less expensive than the little manufacturer brand bottles. Never a problem in 40 years of the stuff, and I still have saws and bikes that I have been running for 40 years.
 
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mustash29

Minister of Fire
Feb 6, 2012
689
SE CT
I run 2 saws - MS-271, 16" with RM3 (standard rounded - green code) and RS (chisel - yellow code) and a MS-391, 20" with RS chains.

I have not cut a lot with the chisel chains, but the original (RM) chain on the 271 cut well and lasted a LONG time before needing sharpened. It's nemesis was cutting about 2 cord of various crap that I got free but had been drug around through the dirt with an excavator by someone who was clearing a bunch of overgrowth.

I'm just shy of ok at hand sharpening (need more practice) but seemed to be struggling to get good result with Stihl files on the RM3 chain. I got a pack of grinding dies for my Dremel tool at Tractor Supply and had great results with them.
 
I run 2 saws - MS-271, 16" with RM3 (standard rounded - green code) and RS (chisel - yellow code) and a MS-391, 20" with RS chains.

I have not cut a lot with the chisel chains, but the original (RM) chain on the 271 cut well and lasted a LONG time before needing sharpened. It's nemesis was cutting about 2 cord of various crap that I got free but had been drug around through the dirt with an excavator by someone who was clearing a bunch of overgrowth.

I'm just shy of ok at hand sharpening (need more practice) but seemed to be struggling to get good result with Stihl files on the RM3 chain. I got a pack of grinding dies for my Dremel tool at Tractor Supply and had great results with them.
Get a 2in1 for that chain ..you'll notice a diff when you use that as to using a dremel ''
 
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