Last weekend I did some load development. Here are the results:

Rifle: Win 70 Classic Super Express 24"
Primers: CCI 250
Powder: IMR4064
COL: Bullet seated to the first cannelure, 91.1mm (3.587")
Groups: 3 shots
Distance: 100m
Altitude: 1000m
Temperature: 25�C (sunny but windy)
Chronograph: PACT at 3m

charge vel sd es Group(mm) MOA
74 2351 14.9 29.8 40 1.37
75 2378 6.0 12.0 45 1.55
76 2414 20.7 41.5 57 1.96
77 2424 6.2 12.5 39 1.34

Although the groups were not exceptional, they are good enough for hunting. The results were very uniform. There were no signs of high pressure... Since I obtained over 2,400 f/s, I stopped at 77gr.

Has anyone experimented with this powder and with different seating depths with these bullets?

Antonio

Antonio,
You can take the load up another couple of grains to give around 2500. The maximum load with a conventional (smooth) bullet of 400 gr is 81 gr of IMR4064. Seat the bullet further out, if the magazine will allow it, and do not crimp the bullet.

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Gerard Schultz
GS Custom Bullets

Antonio,

I did, and reported it on:

http://www.serveroptions.com/ubb/Forum16/HTML/000305.html

I don't remember if I reported it, but I used a Lee factory crimp. Given the similarity of IMR4895 and IMR4096 in this case, I don't understand why you did not get better groups. Did you get all previous fouling out of the barrel?

Does that rifle shoot well with other bullets?

The sd and es are bigger than I got with the surplus 4895, I wonder if that's a factor? I used WLR primers, don't know if that matters much, but I seem to

Gerard's printed directions say do one load progression to pick velocity (I chose 2450 fps), then vary the seating depth on that load to get best accuracy. I did not have to do that, but maybe you should try it?

Good luck,
Don

Thanks very much Gerard and Don...

Gerard:

I am limited by magazine length to 91.5 mm OAL. I got only 38 bullets left, so I will experiment by varying seating depth with a couple of them around 77gr. I am content to shoot my next buff at 2425 f/s at a somewhat lower pressure.

So far, I think your bullets are great Gerard. They look awesome and considering my post-taliban finances, I am even considering robbing a bank to try them asap on a buff in Africa.

Q: Since your FN bullets do not have an ogive, what is really the effect on accuracy of varying seating-depth slightly, since the rifling will only engage the bullet at the first band?

Don:

The rifle was clean (Barnes CR-10). Exceptionally, I have shot in the past a few 3-groups with this rifle at 100m that went as low as 12mm (0.41 MOA) with Hornadys 400 gr RNSP and 7mm (0.24 MOA) with Barnes XFB 400gr. However, its (and my...) typical average performance off the bench with 5-groups at 100m has been between 1 and 2.0 MOA. I was envious of your group...

Thanks again, Antonio

Antonio,
Varying the seating depth also varies barrel time and the possibility of finding the sweet spot when the barrel is having a "quiet moment" as the bullet releases from the muzzle.

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Gerard Schultz
GS Custom Bullets

A 416 that shoots 1.5" at 100 will probably surfice, all else is piddle considering its use..I would crimp lightly regardless to asure no setback. I'll bet you don't shoot any varmints with it and that you will get your buffalo every time.

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Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

Antonio,
For field use, I would agree with Ray on the light crimp. Gerard told me not to also. Accuracy seems to be good either way with mine.

Did you get the play in your bolt action figured out? I guess so if you are testing loads in the same 416.

BTW, I am assuming your bullet is the 380 grain FN. I didn't see bullet weight specified on my first perusal, but maybe CRS has struck again. Gerard also has a 410 grain FN and a 330 grain HV.

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So many bovids! So little time and money!
RAB

Ray:

Due to the immense difficulty in obtaining components over here, normally I do not like to get involved into too much group and velocity paranoia, but I will try Gerard�s suggestion to see if there is an improvement.

I have shot two buffalo, an elephant and 3 hippo with that rifle and its 1.5 MOA accuracy and they all died happily. When I learn how to manipulate photos I will post them...

RAB:

You are correct in that it is the same rifle (the only biggy I got). I have been with it to Africa 3 times and it has worked well so far.

I got basically two hypotheses on the rifle�s problem:

1) The coned section of either the action or the barrel is outside tolerances.

2) The locking lugs have been set back and there is headspace.

Since the rifle shoots well, and I do not shoot above maximum loads,and there have been no problems with case separations (I have been able to reload brass up to 8 times...), the most probable explanation is 1). The person who thought about 1) is a gunsmith who posts in HA and he said there was no major problem. That the solution was to take a turn off the barrel and rechamber, but that it was not really necessary.

I would like of course to have a gunsmith look into it if I knew one I can trust over here. There is not much experience with big-bores left in the gunsmith pool in Mexico.

Maybe next time I go to Africa I can have a gunsmith look into it in say Atlanta or Joburg...

Regards, Antonio

Antonio,
Have you any stainless shim stock? You can make up some .005" discs and see if you can close the bolt on a cartridge with 1,2, or 3 shims up against the boltface. At the very least this will provide an approximation of headspace and possibly verify or eliminate it as a factor.

Nickudu:

That is a great idea...!

As a matter of fact I have some shims, since I recently bought a kit with 12 sizes from Brownells that goes all the way to 0.001".

How could I proceed to simulate a go-no-go process?

Should I use a factory cartridge or empty brass and work up shims until the bolt does not close or should I use an empty cartridge fired in my chamber?

Regards, Antonio

Antonio,
I would suggest you ask someone here who may know the current acceptable factory headspace parameters for current production Model 70's. I hesitate to state what it may be, my friend. All I can tell you is that I use the following method upon receiving any new rifle for baseline data:

1. - Remove Firing pin
2. - Chamber a new factory round with a .005" shim stuck to the boltface with vaseline or a light dielectric grease.
3. - Assuming full, unimpeded closer, chamber the same factory round with a second .005" shim stuck to the boltface.
4. - Repeat, slowly, with a third .005" shim and see how far the handle down without excessive force. Usually you will feel a "wipe" of resistance somewhere between the second and third .005" shim. If this occurs, back off to a .003" shim for the final shim and try again for full closer. As necessary, keep backing off your shim stack in .001" increments until the bolt closes with a nice firm feel. This is about all the headspace in "your" particular rifle.

I have the same rifle as yours, also in .416 Remington and it has .012" headspace as per this admittedly less than perfect method. I will not say if this is too much but I think it is not. Maybe John Ricks or someone else here can offer a better guess than I, on this.
So, It is my view that if your gun indicates
.012" to .015" clearance with this method it does not have a headspace problem. I have had a few SAKO and Remington rifles that showed .018 - .020" or a touch more and they seemed to function just fine with brass showing no sign of stretching.

[This message has been edited by Nickudu (edited 12-15-2001).]

Nick,

I also don't know the spec on headspace for the 416.

I seem to remember that the NOGO gage on a 308 is +.004, the field gage is +.008.

You are not supposed to shoot a 308 with .008 or more headspace. I suspect that the .416 limits are about the same.

The case will never be maximum dimension either, so usuing your method .010 seems safe. .015 seems 'way too loose. The gages are only about $20 and are common for all belted cases, so in the US I'd just buy them. (I have a friend that has a set! )

Don

Don,
No argument. My premise is based on NOT having gauges available. If the brass is not stretching after a reasonable number of firings, I see no cause for concern. I have not found a factoty rifle giving < .010" in years. Let's see what Antonio finds ... should be fun.

Welcome to barnyard gunsmithing 101...

If you think that you have headspace, don't shoot that rifle, it could be dangerous and needs to go to a qualified gunsmith...

Barnyard check for gunsmithing...take off the extractor and take out the firing pin then cut a piece of electricians tape and stick it to the bolt face then close the action on a empty resized round, it should close easily, now try two layers, that should be very snug indeed, if not then you need some repair work done. It should not close on 3 layers...Of course you can force anything so don't do that.

A clue of head is firing a primer and see how far it backs out..but all this is barnyard stuff just to discover a problem exists...

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Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

Nick,

I wasn't trying to argue or correct you, just clarifying for any readers not working under an importation handicap.

I have found that most new Remingtons will close on a Field gage (+.008). (Even the supposedly high end ones.) Most new Brownings and Winchesters would close on the NOGO, but not on the Field.

Don

I understand that Don.

There are other real factors in this and one of the more prevalent is the variation of belt location. There is potential for anywhere from .003" - .005" variation between brands and even lots of the same brand. You can see how that might serve to confuse the issue.

The problem being in many cases that a lot of folks don't know how to use headspace gages...You can, most of the time, close a no go on most guns but it takes some effort and that can, in fact, damage a chamber. It is a feel...

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Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

What Ray says is correct and is just one more reason I feel it worthwhile to employ the above described method to establish ones baseline data upon taking posession of a rifle and, once again, if you elect to lap the lugs. This allows you to monitor set back or determine what is happening should headspacing become suspect down the road.
Most often, excessive case stretching or an actual casehead separation will occur before a shooter begins to think about such things as proper headspace.