Author Topic: Rimmed verses Rimless (Read 1443 times)

jeepmann1948 · « **on:** February 24, 2013, 03:58:05 AM »

Have any of the 307/308, 7-08/7-08R, 358/356 243/243R conversions actually seen any accuracy gains from the rimmed conversions? I have had the rimmed conversions on the burner for over a year but with work and other stuff it has been put on the back burner.
Thanks
George

petemi · « **Reply #1 on:** February 24, 2013, 04:39:53 AM »

It sounds like something I ought to get into this Spring with the .356/.358. I can do it with both new and fired brass. Might be interesting.

Pete

gcrank1 · « **Reply #2 on:** February 24, 2013, 05:04:02 AM »

Its a good question, I'll be interested in the response, but IMHO the only thing the rim will do is give proper headspace to an improper chamber and purchase for the extractor/ejector. In my messing about with single shots of several makes the chamber and especially the throat are what gives the accuracy (accepting that the barrel is decent, of course), not the base/rim.
Put another way, a rim cut to take rimmed cartridges, otherwise identical in load and ballistics, will not turn a so-so shooter into a tack driver.
But iffn it works for you I'll be glad for ya

.

LaOtto222 · « **Reply #3 on:** February 24, 2013, 06:10:03 AM »

I have not taken a rimless case and test fired it, then cut a rim in and test fired again to see if you gain anything. I would suspect you would gain nothing as far as accuracy is concerned. My understanding is, if a case has a rim, you get best accuracy if you head space off of the shoulder, not the rim. Some cases such as the 22 Hornet and to a certain extent the 30-30 do not do a very good job of head spacing off the shoulder because the shoulder is too sloped to do so. Many early cases were head spaced off of the rim and had very sloped shoulders or no shoulders at all. A modern rimless design forces you to head space off of the shoulder and thus, in general, has better accuracy than a rimmed design. With all of that said, I still prefer a rimmed case in a break open single shot. Why might you ask? No real solid reason, I just think break open rifle and rimmed in the same vein.

Rimmed vs rimless has been debated here many times and some people have strong feelings both ways. My personal feeling is do what you like, feel comfortable with. I have seen rimless designs shoot well and I have seen rimmed cases shoot well. So once again, it is a matter of preference. I have 6 different barrels and only 1 is rimless, a .223 Remington 24" Bull. It is not my most accurate barrel, but not because it is rimless.

Good Luck and Good Shooting

petemi · « **Reply #4 on:** February 24, 2013, 06:28:19 AM »

I have some extremely accurate Handis. The .45-70, .30.30, Maxis, .243 and 7mm-08 (with certain loads). Some rimmed, some rimless. I don't think accuracy is based on that. I do favor the rimmed in an extractor because they're easier to grab. My question is, for example, is it possible for my .356/.358 to shoot the exact same load from the same rifle and get better accuracy out of one or the other, rimmed or rimless. I doubt if I'm gonna find much, but I'm retired and have time. Besides, it's just another excuse to shoot

Pete

bucmeister · « **Reply #5 on:** February 24, 2013, 07:32:50 AM »

Pete,

I think you hit the nail on the head as far as testing the accuracy of rimmed vs rimless rounds and that is that it has to be in what I would call a dual use chambering, that being the 356/358 or the 307/308 for example. At least would seem to be the issue as I understand it.

ibgp3 · « **Reply #6 on:** February 24, 2013, 08:07:11 AM »

I have a couple of Handi's in 6.5 Creedmoor that I had rimmed.
I've made brass from at least 15 different cartridges and several headstamps in some.
When I was fire-forming brass made from .270 Win I noticed pressure signs from medium pressure loads.
That made me test case capacities for fireformed 6.5CM cases made from various cartridges and headstamps.
..... I found a range from 49.15 to 52.8 grains of water.
I also found that some headstamps have much more capacity range than others.
Cartridges made from 444 Marlin and 307 Win have a large range of capacities.
Cartridges made from 270 Win have a much smaller range of capacities.
Good loads in cartridges with a wider range of capacities have a wider range of velocities.

Point: Rimmed versus Rimless accuracy questions will require a lot of details and testing before the answer means anything.

cwlongshot · « **Reply #7 on:** February 24, 2013, 08:26:02 AM »

Quote from: jeepmann1948 on February 24, 2013, 03:58:05 AM

Have any of the 307/308, 7-08/7-08R, 358/356 243/243R conversions actually seen any accuracy gains from the rimmed conversions? I have had the rimmed conversions on the burner for over a year but with work and other stuff it has been put on the back burner.
Thanks
George

Oh now you have done it...

IF any differences turn up, EITHER WAY, it is THAT GUN with THAT loading... In and of themselves, one has no accuracy advantage over the other...

Now, having said that, we can get way out in left field, an start talking about the proper/consistant head space as it pertains to accuracy. In that I would side with rimmed case in a single shot. But assuming both are properly chambered and head space is correct for each, the accuracy aspect is moot.

CW

hoytcanon · « **Reply #8 on:** February 24, 2013, 08:47:39 AM »

Quote from: cwlongshot on February 24, 2013, 08:26:02 AM

IF any differences turn up, EITHER WAY, it is THAT GUN with THAT loading... In and of themselves, one has no accuracy advantage over the other...
But assuming both are properly chambered and head space is correct for each, the accuracy aspect is moot.
CW

If rimmed and rimless don't matter... where can I get me a "moot???"

petemi · « **Reply #9 on:** February 24, 2013, 08:53:08 AM »

Which one do you want.....a Moot or a Moot R

We have both.

Pete

jeepmann1948 · « **Reply #10 on:** February 24, 2013, 09:05:36 AM »

Ok guys please keep it on the subject

Looking for experiences not conjecture
Thanks
George

hoytcanon · « **Reply #11 on:** February 24, 2013, 09:33:54 AM »

Quote from: petemi on February 24, 2013, 08:53:08 AM

Which one do you want.....a Moot or a Moot R We have both.

Pete

Apparently it doesn't matter...

gcrank1 · « **Reply #12 on:** February 24, 2013, 10:10:03 AM »

George, I thnkin' it might have to be you that does the complete, comprehensive accuracy trials with your rifle and best load, over time so its not just one 'braggin' group' on one great day, then rim the chamber and do the same with rimmed cases that are as close to the same capacity as the rimless and work up the database for the mean group size on both, "complete with circles and arrows, and a paragraph on the back of each, telllin' what each one is about".
OR, just do it 'cause you want a rimmed case option, which is all it really needs to be to go for it, 'cause accuracy is a fickle mistress' (and you can quote me on that

).

cwlongshot · « **Reply #13 on:** February 24, 2013, 10:26:24 AM »

Quote from: hoytcanon on February 24, 2013, 08:47:39 AM

Quote from: cwlongshot on February 24, 2013, 08:26:02 AM
IF any differences turn up, EITHER WAY, it is THAT GUN with THAT loading... In and of themselves, one has no accuracy advantage over the other...
But assuming both are properly chambered and head space is correct for each, the accuracy aspect is moot.
CW
If rimmed and rimless don't matter... where can I get me a "moot???"

I am saying, rimmed to rimless, as it pertains to accuracy is moot...

For many years, rimmed cases where the most accurate. That's MOSTLY because of the actions they where fired in and the fact that rimless where not yet widely used. Most forward 20-30 years and semi autos, magazine fed firearms needed rimless cases and they now dominate. Again mostly because rifles that use rimless are more popular today. The rimmed or rimless is a product of the time and actions used. Not so much accuracy differences.

I have a 307/308 and a 356/358. Both shoot great, both of mine shoot rimmed better. BUT that's because I don't shoot much/any rimless out of them.

Thats all I meant.

CW

gendoc · « **Reply #14 on:** February 24, 2013, 10:55:38 AM »

one is no more accurate than the other, if you know what yur doing handload'n to yur like'n.
ones remark mite be sumone else's BS alarm........... and yes it happens here !!!
i really don't giva hoot what ya shoot..........its my and mine that matters to me.
so have at it with what ever blows yur mind.
yall hava great even'n... i will !! as its written................

Dinny · « **Reply #15 on:** February 24, 2013, 02:23:57 PM »

It seems to me that one way the rims could affect accuracy is if you own one of the problematic Whelens. I had one and after three FTFs in a row I quit concentrating on accuracy when I shot. If it were rimmed and fired each time I would have gotten better accuracy.

Thanks, Dinny

theratdog · « **Reply #16 on:** February 24, 2013, 03:46:38 PM »

the only time it makes a difference to me is what i am hunting.

hoytcanon · « **Reply #17 on:** February 24, 2013, 05:52:22 PM »

Quote from: cwlongshot on February 24, 2013, 10:26:24 AM

I am saying, rimmed to rimless, as it pertains to accuracy is moot...
I have a 307/308 and a 356/358. Both shoot great, both of mine shoot rimmed better. BUT that's because I don't shoot much/any rimless out of them.
Thats all I meant. CW

I knew what you meant CW... I was just being a goofball...

nanuk-O-dah-Nort · « **Reply #18 on:** February 25, 2013, 08:55:52 AM »

Quote from: petemi on February 24, 2013, 06:28:19 AM

I have some extremely accurate Handis. The .45-70, .30.30, Maxis, .243 and 7mm-08 (with certain loads). Some rimmed, some rimless. I don't think accuracy is based on that. I do favor the rimmed in an extractor because they're easier to grab. My question is, for example, is it possible for my .356/.358 to shoot the exact same load from the same rifle and get better accuracy out of one or the other, rimmed or rimless. I doubt if I'm gonna find much, but I'm retired and have time. Besides, it's just another excuse to shoot

Pete

it seems to me, that with differences in case capacity, the comparison is not accurate.....

it would be better to see if you could develop a more accurate load, one over the other, using whatever techniques you had too....

knight0334 · « **Reply #19 on:** February 25, 2013, 09:01:58 AM »

Quote from: hoytcanon on February 24, 2013, 08:47:39 AM

Quote from: cwlongshot on February 24, 2013, 08:26:02 AM
IF any differences turn up, EITHER WAY, it is THAT GUN with THAT loading... In and of themselves, one has no accuracy advantage over the other...
But assuming both are properly chambered and head space is correct for each, the accuracy aspect is moot.
CW
If rimmed and rimless don't matter... where can I get me a "moot???"

The only bearing a case on accuracy is the way it propagates the burning of the powder. All the case does is hold the powder, bullet, and primer in a tidy singular package, then acts as a gasket to seal the chamber once it is ignited.

Accuracy is 99.9999% driven by the bullet/powder charge to rifling twist rate, the barrel itself, and the person pulling the trigger. The case plays little to none in the accuracy of the platform.

SHOOTALL · « **Reply #20 on:** February 25, 2013, 09:21:33 AM »

When the extractor slips past a rimless case on opening the action you will then have an opinion . A very strong opinion. If you shoot alot of reloaded ammo and ever get some with the shoulder set back a bit to far or the primer a bit deep (crushed) you may not be able to fire rimless where you might rimmed. You could get into the footprint of the base and spreading impact over a wider area and how it may cause the action to flex. Depending on your chamber factory ammo may or may not fire as well in one or the other but with a rimmed case it should fire. So there is little way to know which is more accurate really but both can be very accurate.
Now the real ? with out a rim how on earth do you hold the two extra rounds between your fingers with out them slipping out during recoil ?

petemi · « **Reply #21 on:** February 25, 2013, 09:44:18 AM »

Nanuk, the case capacity of the .356 Winchester and the .358 Winchester is identical. Ask any real person who has compared them. I believe CW and Dinny have. I've metered both, and they are the same. Yes, I have read so called Gun Writers to the contrary....but I've done it. Shooting a Handi, and not a levergun, I load pretty close to .30-06 and .35 Whelen levels in both .356 and .358 with no problems........ Same primer, powder, and bullet...results?....same accuracy and velocity and a surprisingly flat trajectory. Not so much for paper punchers as for hunters, but this combination tosses a .35 caliber bullet at very respectable 30 caliber velocities.

SHOOTALL....What extra rounds? For what?...ARs carry extra rounds for any perceived emergency......that emergency being the owner usually can't shoot well enough to smack a target with one shot. If ya gotta carry an extra two, ya just stick em in yer mouth. Grandpa taught me that.

Pete

SHOOTALL · « **Reply #22 on:** February 25, 2013, 10:27:22 AM »

Quote

SHOOTALL....What extra rounds? For what?...ARs carry extra rounds for any perceived emergency......that emergency being the owner usually can't shoot well enough to smack a target with one shot. If ya gotta carry an extra two, ya just stick em in yer mouth. Grandpa taught me that.

Pete

Here we can shoot two deer at the same time

or a pack of yotes

I hate slober on my projectiles

gcrank1 · « **Reply #23 on:** February 25, 2013, 10:35:58 AM »

My 'magic bullet lube' secret is out..........

nanuk-O-dah-Nort · « **Reply #24 on:** February 25, 2013, 10:59:26 AM »

Quote from: petemi on February 25, 2013, 09:44:18 AM

Nanuk, the case capacity of the .356 Winchester and the .358 Winchester is identical. Ask any real person who has compared them. I believe CW and Dinny have. I've metered both, and they are the same. Yes, I have read so called Gun Writers to the contrary....but I've done it. Shooting a Handi, and not a levergun, I load pretty close to .30-06 and .35 Whelen levels in both .356 and .358 with no problems........ Same primer, powder, and bullet...results?....same accuracy and velocity and a surprisingly flat trajectory. Not so much for paper punchers as for hunters, but this combination tosses a .35 caliber bullet at very respectable 30 caliber velocities.

Pete

thanks for that Pete.

I initially was thinking of factory rounds, which the 308 win has 0.150 overall length advantage so with identical bullets, there is a slightly reduced case upon initial firing.

that would create a situation where the Chamber Pressure would be lower for the 307 than the 308 in the same chamber.

not an issue with handloading.

so if the work has been done to all practical extent, what was the question again?

As Petemi said, they are the same. Excepting the rim, there is no difference.