I was able to work up my first series of loads for my new 7x57 rifle. Its been a long time since I have reloaded for any of my rifles. I started with Norma brass, WLR primers, Nosler 140gr partitions and IMR4350. The good news is that I worked all the way up to 52grs before I had any signs of high pressure. At 52grs I got 3040fps with a .75" group which was far beyond my expectations with the McGowen 26" barrel.

So.... the problem is that I am having trouble getting the bullet seated straight. I had several of the loads that would not chamber and It appears that the bullet is not straight. I am not crimping, resizing the neck only, trimmed cases to 2.25" so it should be square. What could I be doing to cause this?

I would start by taking apart the seater die and checking the cup. Possibly some crud stuck up there, or it doesn't match the ogive of your bullets.

What type of rifle?
I had one that had a chamber some what out of round.Had to full length re-size them to get them to work.
Guess they found their way after that.
Oh I was using H-414 powder with 140-154 grain bullets with some 170s thrown in for fun.

quote:

Originally posted by plainsman456:
What type of rifle?
I had one that had a chamber some what out of round.Had to full length re-size them to get them to work.
Guess they found their way after that.
Oh I was using H-414 powder with 140-154 grain bullets with some 170s thrown in for fun.

I don't think it is the chamber. When I pull the cartridge that will not chamber out of the gun there is a mark on one side of the bullet like its touching one side. And not matter how I turn it, it still makes another mark in the same area.

First off, I think you need to address the fact that you are running way hot if you're getting 3100fps with a 140gr in a 7x57. I don't know what you call "pressure signs" but you're way out of the book. The Lyman 48th list a max of 478grs of 4350 and that's a compressed load. How're you getting three more grains of powder in the case??

The rub mark could just be a rough spot on your feed ramp. Have you looked into the chamber and the action to see if something "jumps out" at you? Also, if your bullets are crooked, you could have a mis-adjusted seater die.

You say it's a Mcgowan barrel. Have you talked to the smith that chambered and mounted it?

quote:

The good news is that I worked all the way up to 53grs before I had any signs of high pressure. At 53grs I got 3140fps

Good news? While the modest maximum SAMMI pressure of 45,000 CUP for the Mauser can be exceeded safely in a strong action, most powders on Hodgdon's website will not get that velocity from a 7mm Remington Magnum at over 50,000 CUP. No 7x457 will equal a 7mm Magnum. I suspect the chronograph is faulty - any load giving that velocity would surely show high pressure signs.

Too, every loading manual I checked had a case length of 2.235", not 2.25". Hope your chamber is a long one.

I once had an RCBS FL die which had warped during the hardening process, making 'bent' cases. It is possible that your die is faulty too, or has the issues commented on above.



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Definately not the gun. Chamber looks good and I had two additional 7x57 rifles at the range to sight in. So I checked feed in those guns as well. The gun feeds 6 different factory loads just fine.

As to the hot loads, its 3040fps with 52grs sorry had to correct that. My other custom 7x57 maxs out at 49grs of 4350. The first sign of high pressure on the new gun was a slight flattening of the primer. My goal was to get 3000fps with a 140gr bullet. So I can back it down a little. Another strange thing is the best groups were the hotter loads.

He is using a 26" barrel which may give reason for the increased velocity...

Maybe post this in the reloading forum?

I'd also be a bit concerned over the velocity.

Too many potential problems really...

1. Failure to chamber - neck sizing only may indicate that you need to size more and "bump" the shoulder. Partial sizing can increase the case headspace.
2. The COL may be too long so the bulet is engaging the rifling (any marks on the bullet?)
3. Is the case trimmed to below max case length? If not you may be effectively crimpng the bullet in the rifling and pushing up pressure. It can be dangerous...
4. If the case mouths aren't square you can get seating that it not aligned.
5. So too if you don't lightly chamfer the case mouth, but probably not visible to the nakes eye (well not for us mortals).
6. You can be bottoming out the bullet tip in the seater plug which will also cause seating to be off, but that's common with the new sharper pointed designs and unlikley with a Partition.
7. Are your case necks straight out of the sizer die? Skew necks = skew bullets...
8. Then things like die and press set up and issues etc.
9. Is this new brass, or has it been fired in another rifle? If it's secondhand it may simply be a case of different chamber dimensions (headspace).
10. Does the sized brass chamber without the bullet?
11. Does the unsized brass chamber without the bullet?

If you can borrow or have a runout or concentricity gauge you can try to determine at what step the problem is creeping in.

Those are the first ideas that come to mind. There are probably others if I think a bit, but I'd start there.

quote:

He is using a 26" barrel which may give reason for the increased velocity...

Uh, no. If a 7mm Magnum has trouble getting over 3100 fps with a 26" barrel, there is simply no way a 7x57 can get there with the same pressure. Someone run a QUIKLOAD on this.

Using flattened primers as an indication of high pressures is fraught with inaccuracies and is SO 20th Century. What is the case head growth? Expansion ring growth? Ease of seating new primers? Getting abnormally high velocities is an established, clear indication of high pressures. The world is full of reloaders who think their loads are safe because their gun does not blow up. Good luck.


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quote:

Originally posted by KurtC:
I would start by taking apart the seater die and checking the cup. Possibly some crud stuck up there, or it doesn't match the ogive of your bullets.

KurtC, I think you were close. I was using a "micro" adjustable seating die that I have not used before. I switched back to the regular Lyman seating die and worked up another series of loads. 15 total rounds and they all feed perfectly. I went back down to 47grs and trimmed the cases to 2.244" and oal 3.035" to see if I could get better accuracy and worked back up to 50grs. I was at the range at daylight this morning to give'm a go. (mardi gras holliday) 50grs of IMR4350 gives me 2935fps with a 3/4" group. It was the best group of the 5 loads and I'm pretty comfortable with that velocity. I will try to tweek that a little to get the group size down, I hope.

Some info on the barrel length. The barrel on this gun is 26" and is a very lightweight contour. I experimented several years ago with various barrel lengths in the 7x57 caliber. I have since lost the data on my computer but I tested 20", 22", 24" & 28" barrels using Norma factory 150gr ammunition. The increase in velocity from 20" to 28" was nearly 150fps. I used the 26" barrel because it looks good, balances good and I hoped it would give me better velocities. And it does. I get 2648fps out my old custom rifle 22" bbl with Norma 150gr factory ammo and 2762fps from my new rifle same ammo. Thats a 114fps gain. Now I realize that there may be other factors that effect that gain but I think its mostly the barrel length. So, should I be concerned that my handloads are producing higher velocities than the reloading manuels say they should? Well... I kinda expected and hoped thats how it would go. My main concern was having good accuracy which seems to be fine. The guys at McGowen barrel didn't want to cut the barrel as light as I wanted in that length, so I had to get my gunsmith to do it. They were concerned about accuracy as well. I'll take 3/4" groups in this setup. After all it was never intended to be a benchrest rifle.

Thanks for the help and concern.

A simple QL run says that to get 3040 from 52 grs of IMR 4350in a 26" pressure would be at least 63806psi.

So in theory it is doable.

QL may be right. I have checked my hot 7x57 loads in Win. brass only with 52 grains of H414 and a 140 grain bullet, just under 3000 fps and 63000 psi if I remember right. This is in a really long throated Ruger and Win brass, so don't try this in a Win 70. I have shot thousands