How to measure chamber and slug bore of Ross M10?
- Thread starter Kirk1701
- Start date
That's strange. I'll have a closer look.
I'd like to try the partial neck-sizing you suggest, but I'm not sure what size o-ring I should be using.
The O-ring trick is best applied to the first firing of new brass, I doubt it would benefit a partially resized case. Regardless, using the O ring may lead to the same problem I described in my original post. I should point out that partial resizing is advantageous over neck sizing when you want to shoot the same brass in several rifles - you just resize to the tightest chamber. This is where you get into problems with the Ross, as you cant gage whether the brass is sized correctly or not, except by shooting it. If you keep your brass segregated to the given Ross, then you should be able to partially resize - if you know what you're doing.
I'm just trying to decide if it's the right option for me. Having not reloaded any rifle cartridge, I'm starting with factory .303. These cases I intend to reload. I have a second-hand set of RCBS full-length dies. I want to get as much case life as I can, so I'm exploring the usefulness of the o-rings for ME. Options for several rifles really don't apply...yet.
Are you recommending against the o-ring?
Would the partial sizing Tinman points out assist me in case life or are we talking increments?
The o-ring trick is helpful if a rifle has generous headspace, and it is desirable to fireform the cases to the chamber, without risking incipient separations.
If your rifle has good headspace, it won't make much difference.
Shoot the rifle. Inspect the fired cases. Are they dramatically fireformed? Do they look quite different than an unfired case? If your rifle has the enlarged chamber, it will be pretty obvious.
Run the cases far enough into the die that a bullet will be held securely. If the rounds chamber freely, it will not be necessary to set the shoulder back or set the die so that it contacts the shellholder.
If your rifle has good headspace, it won't make much difference.
Shoot the rifle. Inspect the fired cases. Are they dramatically fireformed? Do they look quite different than an unfired case? If your rifle has the enlarged chamber, it will be pretty obvious.
Run the cases far enough into the die that a bullet will be held securely. If the rounds chamber freely, it will not be necessary to set the shoulder back or set the die so that it contacts the shellholder.
I think your best bet is to fire your factory ammo and then start FL sizing your brass. If you say have 3 boxes if ammo to shoot that's 60 rounds. Multiply that by the amount of times the brass can be FL sized (5-8 times in my experience) that's 300-480 reloads to shoot before your brass wears out.
By the time your brass wears out you can decide wether you shoot .303 enough to want a neck sizing die. I bought mine from wholesale sports, think they were $45 which is the price of another bag of brass.
The reason that I necksize is that I have 4 rifles that shoot .303 and I shoot them all at least once a month. So I go through at least 200-300 .303 rounds a month. I'm a benchrest shooter so accuracy is very important to me so necksizing helps in some cases.
Lastly I don't have to lube my cases to necksize them, which cuts prep time while reloading.
Anyhow, start by FL sizing your brass and order a necksizing die later if you so desire. I have one batch of ammo for my Ross that I FL sized 5x and I've necksized them another 6-8x and they're still good.
As for the O-ring trick, I use it on any of my .303's when I'm fireforming the brass for the first time. I find the brass sits straighter in the chamber and fireforms more uniformly. It's not always necessary on all rifles and I'd have to say that you should be fine not doing it on your Ross.
Well, the cases came out definitely fired, but not dramatically different that the loaded rounds. There is some slight ballooning in the case head separation area. The shoulders are visibly blown out, but not strangely misshapen. Everything is expanded quite evenly all around the case, as you would expect from a finely machined rifle.
I'm extremely impressed with this rifle. I was only shooting at 50 yards to just get a feel for the rifle. It was hitting high and right as expected. I was shooting at 5" plates and had to hold in the dirt to hit them. If I held 6 o'clock on the 5", I'd smack the 2" plate just above and to the right. I'm looking forward to stretching it out to 200 yards to give the lead a chance to flatten out.
I'll also allow some cool down time between shots. I was having so much fun, I went through my paltry 20 rounds in no time and the barrel was extremely hot. Not good for preservation. But I had fun.
Here's a question, just how does that magazine cutoff switch work? As I understand it, down is for repeat firing. I wasn't able to pick up a round once I'd loaded the mag. So I switch to the top and all the rounds flew out, lol!
I'm extremely impressed with this rifle. I was only shooting at 50 yards to just get a feel for the rifle. It was hitting high and right as expected. I was shooting at 5" plates and had to hold in the dirt to hit them. If I held 6 o'clock on the 5", I'd smack the 2" plate just above and to the right. I'm looking forward to stretching it out to 200 yards to give the lead a chance to flatten out.
I'll also allow some cool down time between shots. I was having so much fun, I went through my paltry 20 rounds in no time and the barrel was extremely hot. Not good for preservation. But I had fun.
Here's a question, just how does that magazine cutoff switch work? As I understand it, down is for repeat firing. I wasn't able to pick up a round once I'd loaded the mag. So I switch to the top and all the rounds flew out, lol!
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- Location
- Beaverlodge, Alberta
I only have one Ross here out of my four in .303 cal that blow the necks out. Now using advice given here I'm even reloading those with good success. The neck collet sizer will not work to size those cases though, I had to use a .308 Win RCBS neck sizing die. The collet die would collapse the neck down into the shoulder. I believe the collets get opened up too much by the blown out neck and pinch brass between themselves on the down stroke and wind up pinching the neck and collapsing it down. With the RCBS dies, good annealing and lube I've had no more troubles.
I looked through all the brass and it appears that only one of the cases has a blown out neck. I believe it was the first one I shot. The rest retain some sharp shoulders. Strange. It's an adventure.
I'm going to begin by full length sizing, since that's what I have. If I start to run into trouble, I'll get a collet die of some sort.
I'm going to begin by full length sizing, since that's what I have. If I start to run into trouble, I'll get a collet die of some sort.
You don't have to adjust the FL die all the way down till it hist the shell holder. Try it with clearance enough to slip a nickle between the die and shell holder at the top of the stroke. Size a hand full of fired cases and see if they will chamber in the rifle. If they do, use that setting and avoid over-working your brass.
Lube the cases as per normal.
Lube the cases as per normal.
Excellent advice! I shall proceed (once my dies arrive). I'm thoroughly enjoying this process.
- Location
- Beaverlodge, Alberta
H4895
