Author Topic: BC 45-70 cartridge question (Read 1513 times)

kevinsmith5 · « **on:** July 18, 2008, 02:56:28 PM »

After firing in my new BC all my cartridges look slightly Flared out down at their base. They almost look like some sort of belted magnums. IS this an issue? I've seen this in factory Hornady (Leverevolution) Winchester (300gr FNHP), and handloads loaded to the lowest pressure level my Lee loader card came with.

tykempster · « **Reply #1 on:** July 18, 2008, 03:17:58 PM »

Yes that is a big issue, quickdtoo should be here soon to help you sort it out!

kevinsmith5 · « **Reply #2 on:** July 18, 2008, 04:01:02 PM »

So is it dangerous? I can't figure out how it can be doing this unless the chamber is too large (diameter) in the area clsest to the breech.

Is that possible?

stimpylu32 · « **Reply #3 on:** July 18, 2008, 04:39:12 PM »

kevin

Anything is possable , can you post a pic of the cases or give some mic numbers to give some idea as to what its doing .

If the chamber was cut with a new reamer it will be on the max side of spec. which will let the case's swell as they are fireforming to fit the chamber .

stimpy

SlimPigguns · « **Reply #4 on:** July 19, 2008, 04:29:40 AM »

Could it be a 450marlin chamber? Sounds like too much expansion to be safe _ Pete

STUMPJMPR · « **Reply #5 on:** July 19, 2008, 05:23:42 AM »

Slim,
that's a good idea...If im not mistaking (which is possible)...The 450 marlin case is pretty close to the 45-70 except for the belted rim to keep from chambering it in a 45-70

quickdtoo · « **Reply #6 on:** July 19, 2008, 05:33:32 AM »

As Stimpy suggested, a pic would be worth a thou....

petemi · « **Reply #7 on:** July 19, 2008, 05:54:23 AM »

I'm no expert by any means, but my thoughts are that it got chambered for the 450, regardless that is a BC and the barrel says .45-70. I'd dump the problem on Remington and let them solve it.

kevinsmith5 · « **Reply #8 on:** July 19, 2008, 06:34:32 AM »

I've pulled the brass out and tried to get a decent picture of it, but this is the best I've gotten with my camera. I'll try to get measurements later with my calipers.

kevinsmith5 · « **Reply #9 on:** July 19, 2008, 06:38:27 AM »

I don't think this looks like enough of a bulge to be 450 Marlin, don't the have a very big belt?

stimpylu32 · « **Reply #10 on:** July 19, 2008, 07:04:52 AM »

Its defiantly not a 450 Marlin so that's a good thing , from what i'm seeing in the pic it looks like you may have a chamber that is on the very max for spec.

How does it shoot ?

Also check your case numbers before and after sizing just to see how much your moving the brass .

stimpy

Smokin Joe · « **Reply #11 on:** July 19, 2008, 07:35:30 AM »

That's just the expansion ring portion of the case after firing. The pressure could be a little elevated. Check the Lee card and see what pressure level you're talking about.

kevinsmith5 · « **Reply #12 on:** July 19, 2008, 08:31:37 AM »

That cartridge isn't a handload, it's a Hornady factory loaded Leverevolution. I got the same ring on every cartridge. Shot 2" groups offhand at 100 yards with Winchesters and Hornady. We won't discuss what it did with my handloads in too much depth, lets just say they did not group well. (first ten cartridges I ever loaded).

stimpylu32 · « **Reply #13 on:** July 19, 2008, 10:24:14 AM »

Kevin

I don't see any reason to be consurned as far as the case expansion goes , worst case you will loose a few times loading the brass due to case stretch , and as for your hand loads not grouping well , that is to be expected with the lowest starting load in a barrel as long as the BC .

The fact that they came out the barrel and the shooter & gun are still in one piece says you did load them correctly , every gun needs to find a load it likes so plan on hammering a few more till it says OK .

Stimpy

kevinsmith5 · « **Reply #14 on:** July 19, 2008, 12:31:54 PM »

They also grouped about 14" lower than the factory Winchester loads at 100 yds.

On the upside they hardly kicked at all.

SlimPigguns · « **Reply #15 on:** July 20, 2008, 03:25:37 AM »

Was it only on the Hornady ammo, or the Winchester as well ? - Pete

kevinsmith5 · « **Reply #16 on:** July 20, 2008, 05:46:47 AM »

Hornady, Winchester, and hanload.

stuffit · « **Reply #17 on:** July 20, 2008, 06:18:56 AM »

I'd suggest a chamber cast. I think Cerrosafe can be obtained from Midway. I wouldn't expect the .45-70 brass, after being fired in a .450 Marlin chamber, to expand and show you a perfect duplicate of the .450. Matter of fact, I'm not sure it would fit in such a way that it would fire, but it might. And, in looking at the picture, I'd postulate that 1) there is a disparity of size in the rear of the chamber. and 2) that the rifle may have been chambered for .450 Marlin and been mislabeled, and 3) I wouln't shoot it any more till the chamber dimensions were certain and/or some other correctable causes of the phenomina is discerned. Invest in some Cerro safe - to be safe.

stuffit

quickdtoo · « **Reply #18 on:** July 20, 2008, 06:39:51 AM »

I find it hard to believe that H&R would cut a chamber for the 450M with a rim cut for the 45-70, if they didn't make the rim cut, the round wouldn't chamber due to the .608" rim. They also test fire every rifle before it leaves the factory. But as stuffit recommended, a chamber cast wouldn't hurt, then you'll know exactly what the chamber dimensions are and you can get the barrel replaced if it's over spec. I agree with stimpy, H&R started making their own .45-70 barrels in the last few months, if they're using a new reamer, it will cut a chamber on the large size to begin with so after it's sharpened a few times, it will still cut a chamber that's not too small. Chamber casting info can be found in the FAQs, Track of the Wolf has the best price on Cerrosafe that I've found at $11.95, Midway wants $20 unless they have it on sale.

Tim

http://stevespages.com/page8d.htm

kevinsmith5 · « **Reply #19 on:** July 20, 2008, 06:51:34 AM »

Taking it to a gunsmith tomorrow. Better safe than head blown off by a ruptured chamber.

stuffit · « **Reply #20 on:** July 20, 2008, 07:05:53 AM »

Welllllllllllll ..... now. We just happened to have a Handi .450 Marlin handy in the house and Quick is exactly right on the "won't chamber" comment. The rim on the .45-70 totally prevents complete entry and/or closing the breech on the .45-70 round in the .450 Marlin chamber. But, from looking at the brass, I believe there is a chamber size issue. Micormeter measurements of the base of the .45-70 brass before and after firing would be interesting but a chamber cast for size disparity or gunsmith insspection are both good options here for the sake of staying on the safe side. Iit'll be informative, I think, to learn what your gunsmiths evaluation reveals.

stuffit

kevinsmith5 · « **Reply #21 on:** July 20, 2008, 08:13:41 AM »

Just finished doing two things. First I polished the brass. Then I broke out the micrometer.

Expansion ring is no longer visible on the Winchester (was always fainter) or the handloads (nickel plated remington brass I bought).

Winchester and remington brass have sarting cartridge max width at base of 0.501 inch. Fired cartridge max width at base is 0.505. Checked several cartridges of both and got same result.

Hornady cartridge max width unfired 0.498 (isn't that way out of spec?). Fired cartridge width is is 0.505. Expansion appears to have only occurred at the last 0.15 inch of case.

The case length on the Hornady is also 2.029 inches, which means I won't be reloading them. Why would Hornady make cases so short? These things shoot 2000 fps plus, wouldn't a shorter case increase pressure?

Does it now appear the problem is not my chamber, but my ammo?

tykempster · « **Reply #22 on:** July 20, 2008, 08:26:29 AM »

The Hornady brass is shorter to allow the longer bullet to be seated out. I don't know why Hornady didn't just seat the bullet deeper though...

Tencubed · « **Reply #23 on:** July 20, 2008, 09:42:48 AM »

Sulfur makes a good chamber cast material. A piece of slightly damp paper towel pushed into the bore works well for a plug. If you put a piece of wire thru this plug and out of the chamber it's easy to pull the cast free. Use this in a well vented area and don't get it so hot it starts to fume as it will burn.

Mike

stuffit · « **Reply #24 on:** July 20, 2008, 10:50:21 AM »

Here are your specs for the standard (probably max) brass dimensions. I'd speculate (again) that the slightly undersized brass, when fired, is creating the illusion of an expansion ring, when there is nothing of any real consequence occurring. You should be able to go ahead with your load development without any more worries about the chamber. But still, a nice chamber cast would provide some interesting information for future reference.

s.

kevinsmith5 · « **Reply #25 on:** July 20, 2008, 02:31:36 PM »

My main concern now is with reloading the Hornady brass. It appears to have expanded only at that one narrow area at the base, while the Remington and Winchester expanded evenly in a gradual taper to the max dimension at the base. The Remington and Winchester are nearly exacty the same as the spec diagram.

Does the Hornady brass have a weaker area near the base? Will this be a problem in reloading?

stuffit · « **Reply #26 on:** July 20, 2008, 06:00:19 PM »

I've never used Hornady brass. I only partial size my .45-70 brass for my BC no matter the manufacturer as long as the fired brass has extracted/ejected freely and chambers freely. It's good policy to use one type of brass in one loading series although not mandatory. I'd think you'll have no problem with reloads in the Hornady brass from a safety perspective. My approach would be to not mix it in with the other two types for the sake of uniformity but, again, that's optional. As long as you follow a policy of using loads from reliable sources, any brass of the correct caliber, regardless of the minor spec differences showing here from your measurements should be OK and safe. Keep in mind that you get your best performance by being consistant with all controlable components. If you don't overwork the bases in the resizing, I doubt there is any innate weakness in the Hornady bases, but again, I've never used it in this caliber.

stuffit

Badnews Bob · « **Reply #27 on:** July 21, 2008, 02:55:23 AM »

You should not have anymore problems out of the once fired brass. People fire form brass all the time to make it fit a chamber it wasn't made for, So really all you have done is fire formed the brass to your chamber. Neck size only and shoot them. IMO they should work well.

STUMPJMPR · « **Reply #28 on:** July 21, 2008, 03:26:59 AM »

Quote from: kevinsmith5 on July 20, 2008, 08:13:41 AM

Just finished doing two things. First I polished the brass. Then I broke out the micrometer.

Expansion ring is no longer visible on the Winchester (was always fainter) or the handloads (nickel plated remington brass I bought).

Winchester and remington brass have sarting cartridge max width at base of 0.501 inch. Fired cartridge max width at base is 0.505. Checked several cartridges of both and got same result.

Hornady cartridge max width unfired 0.498 (isn't that way out of spec?). Fired cartridge width is is 0.505. Expansion appears to have only occurred at the last 0.15 inch of case.

The case length on the Hornady is also 2.029 inches, which means I won't be reloading them. Why would Hornady make cases so short? These things shoot 2000 fps plus, wouldn't a shorter case increase pressure?

Does it now appear the problem is not my chamber, but my ammo?

Looks like you solved your problem the Hornady Brass is undersized....

stimpylu32 · « **Reply #29 on:** July 21, 2008, 04:20:53 AM »

kevin

Another thing to consider is that the hammer type Lee Loader's are a ( NECK ) size only tool and you will not be reworking the cases at the base .

So now that the brass has been fireformed to fit your chamber , you will be able to load all , even the shorter Hornady ones with out any more problems with case expantion .

stimpy