Starting To Reload For A .300 Winchester Magnum

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  • Last Post 23 September 2020
mashburn posted this 24 August 2020

 Hello to all of you cast bullet shooters and re-loaders of all kinds,

By making a trade with another cast bullet forum member, who frequents the pages of the forum, I now have a Ruger NO.1 in .300 Winchester Magnum. I started to load some 170 gr powder coated and gas checked bullets and some 170 grain jacketed bullets. Before much was done, i discovered that the rifle has too much head space and was going to call Ruger tomorrow and see If there was a possibility of shipping it to them. Then I got to measuring the belts in length and diameter and found there was a lot of differences between the different brands of cases. I have never owned or loaded for any type of belted magnum rifle and while my shop was open, I never had a belted mag rifle come in for work. I got on some of the other shooting and loading sites and  picked up a little information, however the cast bullet forum is the only site that I trust with such. Most of the information that I received from our forum is USUALLY CORRECT.

Some people say the case should head space only on the belt, if so the head space is going to vary from case to case. Others say to head space on the shoulder. With the new cases that I bought the rifle certainly has too much headspace if using the belt to measure headspace. Other brands of cases check out fine when checking headspace from the belt.

I'm not going to ask any specific questions, because I feel I will get more feedback if I just let readers chip in any information dealing with different aspects of loading the .300 Win. Mag and along with their rifles and the experiences that they have encountered with such animals. I hope this works as well as playing dumb, which usually works pretty good.

Mashburn

David a. Cogburn

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RicinYakima posted this 24 August 2020

No experience with .300 Win Mangleum. But I worked with a rifle rechambered from 350 Apex to 358 Norma Magnum that had excessive head space if the belt was used. Using .338 Win Mag I expanded and full length resize new cases. Seated a 300 grain cast bullet hard into the throat over 20 grains of A2400. Having left the Imperial Sizing Die wax on the case, they easily conformed to the chamber. Then set the FL die to just size to the shoulder. I have reloaded the cases 4 or 5 times with no problems. FWIW

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Little Debbie posted this 24 August 2020

I’m guessing your Number 1 does not have excessive headspace. I’ll try to keep this short. I’ve loaded thousands of rounds in .300 Winchester for long range target use in custom barrels and factory barrels. Headspace in a “belted magnum” is determined by the length of the belt and I’m guessing if you use a go/no go headspace gauge the rifle would pass at the very worst it would not take a “field gauge”.

Now the belief that the base to shoulder measurement is too long and causes the case to stretch at each firing is correct. This is also true with almost every rimmed case chamber I’ve ever seen . Chambers for rimmed and belted cases seem long compared to rimless bottle neck cases. If you set your full length sizing die to touch the shell holder to resize you’ll induce this base to shoulder shortness and after 2-3 cycles of “full length” sizing you’ll see or be able to feel the case is about to separate just forward of the belt.

There are variations in belt “length” in various brands and lots within brands of belted cases and this is normal.

To make your cases last longer you can easily use a full length sizing die to “partially” size, just touching the shoulder so you shorten the head to shoulder distance just enough to allow the case to chamber easily. The Number 1 does not have much ability to force an oversize case to chamber because of its design, but the technique will work. Just slowly advance the sizing die down until the case will chamber with some “feel”.

Or use a Lee collet die or a neck sizing die. These leave the shoulder alone and will usually chamber in a Number 1 after firing fill loads for 4-6 reloads before needing the shoulder to be pushed back slightly. I base this on the .220 Swift and 6mm Remington Number 1 rifles I’ve owned. I normally stop using any case loaded to full pressure at 10-12 loadings. Sooner if I detect the case is thinning and is going to separate.

In my current Shilen barreled .300 Winchester Magnum with a minimum dimensioned chamber I’ve tried opening the neck to .338” and then setting a false shoulder to get a perfectly formed case for accuracy. Made no difference and was a lot of extra work. I still get 10 full power reloads from my .300 Magnum cases by partially sizing them and setting the shoulder set back with a Stony Point ( now Hornady) headspace comparator system.

I’ve never loaded low pressure cast bullets in a belted case except for .375 H&H and .458 Winchester Magnum. These cases seem to last forever with low pressure loads.

All this being said if you fully resize a rimless shouldered case firing full power loads it will tend to stretch and thin sooner than one that is partial sized, neck sized, or collet sized.

Before going to the effort of sending your rifle back to Ruger find some one with a set of headspace gauges to check your headspace.

This post is intriguing, I may try some cast in my .300 Magnums, Winchester, Weatherby, and Holland & Holland.

What Ric suggested about jamming a bullet in the barrel to hold the case head back on the bolt face with a load that produces enough pressure to form the case to the chamber is a good one and easier than setting a false shoulder. This method seems to prevent much if any thinning of the case forward of the belt.

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Ken Campbell Iowa posted this 24 August 2020

yep, don't use the belt to measure headspace ... use the shoulder.

on my 257 Wea. i used 60 original cases for about a thousand shots and just barely touched the shoulder with my custom rcbs button expander die ...

and you could always use my " CRUTCH but SCARY " headspace gauge .. namely 1 strip of scotch magic tape stuck to the head of several new factory cases ... about 0.003 inch ... should notice it on there, preferably make it crunch when you close the block ... ... and if 2 strips don't stop the block from closing, you need to either fireform all your cases with a trick or adjust the mechanical gun.  ... 0.004 is about as much clearance as i can stand even in a truck gun ... .....   BTW, different brands of headspace gauges give different readings ... 

Trusting that your r1 is ok ... but Verify ...

ken

 

 

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Ken Campbell Iowa posted this 24 August 2020

... thinking about the fancy R1 ... even if a long headspace i would just trick form the cases to fit before i would mess with the barrel ...  let us know how it goes.

ken

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M3 Mitch posted this 24 August 2020

Depending on the vintage of your Ruger, if you send it back to the factory, they may make some other alterations that are not necessarily desirable.  Like replacing the old style and better trigger with the current style.  They will of course fix what is wrong for free, but then again they do reserve the right to just give you a new current production rifle in exchange for what you have.

That said, while I have never owned or shot a 300 Win Mag, I think particularly with a cast bullet load, not a max load but not a squib load either, you can headspace on the bullet, fire form your new cases that way, and for the Win Mag, you can just headspace on the shoulder, neck sizing your cases from then on.  On the 300 H&H, on the other hand, I think a guy is stuck headspacing on the belt.

I think even for full power hunting loads, neck sized cases should be fine, just make sure you test every round that it will chamber, obviously you need to be somewhere other than in the living room while doing this as you are chambering live rounds, I think you can work the action on a #1 while the safety remains on, but anyway I would rather do this where an inadvertent discharge would not be a real problem. 

BTW I like Ken Campbell's rough and ready headspace "gauge". 

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Bud Hyett posted this 25 August 2020

Experience with belted cases was building a .300 Winchester Magnum for 600 and 1,00 yard competition.I researched the winners for action, caliber and load, then dropped by the local benchrest and high-power gunsmith. The project never got too far off ground, I moved to the Pacific Northwest and shot cast bullets. Bought a Sharps for the fun of it.

The first thing the gunsmith said, "Forget all that you read about headspace on the belt, headspace on the shoulder. The only way headspace on the belt will work is to buy a thousand or so cases and precisely measure the belt. The 200 or so that are the same is the dimension I can set it to. That takes a lot of time and money. Or you can set the headspace on the shoulder for a better result."

Farm boy from Illinois, living in the magical Pacific Northwest

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Brodie posted this 25 August 2020

David,

I started loading loading for the 300 Win Mag back in 1968.  I have never had a case separation, and the big guy knows I have loaded some hot stuff in that rifle.  One thing I did and have always done with belted cases is head space on the shoulder.  Basically just neck size and barely kiss the shoulder.  Do not set the shoulder back any amount.  As I am sure you know you can check how much you are sizing a case by just smoking it in a candle flame before it goes in the die and checking how much soot is removed (and from where) afterwords.

Good Luck

B.E.Brickey

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45 2.1 posted this 25 August 2020

The first thing the gunsmith said, "Forget all that you read about headspace on the belt, headspace on the shoulder.

Very Good advice............ The easiest way is Roy Weatherby's method that he used to fire form 220 Rocket cases... which should be modified some as to load intensity (he used full loads). Clean your rifles chamber, load a medium pressure load (somewhere in the 30K to 35K bracket), lube the outside of the case moderately, then chamber and fire. The case will be fully formed and head spaced. After forming your cases, make sure the chamber is cleaned of lube and dry. Resize the case with the die just touching the shoulder with appropriate checks for correct chambering. The cases done this way should last a very long time.

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mashburn posted this 25 August 2020

Hello Ken,

I spotted the sloppy breech block in the rifle before I got to the point of starting to reload. The block has no movement from side to side but will rock like Grandpa's rocking chair if pushed fore and aft. I've checked the head space with a feeler gauge on the head of the case and then close the lever. On the new cases that I bought it will go .005 and if you really force it , it will accept .007 but not so much on other cases. It will close on .005 but you can't pull it out. The clearance is not the result of a chamber that was cut too deep, it's the mortise for the breech block it is too long or the breech block is too short from front to back. I looked in gun parts for a block but they were out of stock. It would take a unfinished block to cure the problem. I'm going to see if Ruger will let me have a unfinished block.

In my years of rifle building I have built about 10 or 12 single shot falling block actions. Some from investment castings and some built from scratch right in my shop. I have had a couple that the breech block fit didn't suit me  but I never fit one as loose as this Ruger. I may send it back to Ruger or I  may re-barrel it, but if you re-barrel you just have the face of the chamber end of the barrel rubbing on the front of the block and still the block doesn't fit the mortise in the receiver. Like I told you earlier, I may make a custom out of it but I would have to have a unfit breech block or set the barrel back. Probably the best be is to send it to Mr. Ruger. Got any idea what the turn around time on this would be?

I have played with making cases to fit rifles a lot of times. But I just have too know in my feeble little brain what is inside of the rifle and it bugs me. Also .007" head space is a heck of a lot. Of course with the big thick web in the .300 Mag case it would probably be fine. I hope someone will write in with rifles that have this much head space.

Mashburn

David a. Cogburn

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Rich/WIS posted this 25 August 2020

No real experience with belted cases but a lot with rimmed cases and don't FL resize.  In 30/40, both original and AI, only neck size and have not had issues with chambering in a Ruger #3 and a Krag. or any signs of case head separation.  NOTE:  the loads were with cast and in the +/- 35K range.

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Ken Campbell Iowa posted this 25 August 2020

i have never had to send a ruger firearm back for service but belong to several ruger groups and it seems 2 weeks is about normal.  Ruger service seems to be outstanding, btw.

i would call Ruger service and discuss the problem before sending it back ...  and keep the name of the promissory service guy/gal... heh.

would love to visit ruger and walk through what they decide on your R1 ...  is it the block or is it the action frame? ... you would suppose they hand fit the blocks to the frame casting . 

and secondly, even if the block is short/mismatch, wouldn't they have just adjusted the barrel to a tighter headspace anyway? ...  even on the big 300 winmag, 0.005+ seems too much.

ken

 

 

 

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mashburn posted this 26 August 2020

Hello Ken,

I got home well after you left me a message tonight. My Grand daughter has been playing in a softball tournament , about 50 miles from here, and we have been getting in late every night. We have a slight reprieve because they don't play again until Thursday night. I was afraid to call you back because you might be in one of your few able to sleep nights. If Ruger chose to set the barrel back that would cause the forearm inletting around the barrel not to fit and the quarter rib also. I wouldn't be surprised if they didn't replace the rifle. I wonder if they have over size breech blocks to take care of such. I held off inletting the forearm after I saw the head space problem. When I call Ruger I'm going to ask if I should go ahead and do the inletting or just send the forearm back as it is, I'll give you a call tomorrow afternoon. I don't know if I will get a chance to call them tomorrow or not. It sure would be nice if they would replace that .300 mag with a .358 Winchester.

Mashburn

David a. Cogburn

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Ken Campbell Iowa posted this 26 August 2020

mr. cogburn .. no, i was up til 5am.. going to try rust blueing with a steam gun .. was you-tubing to see if anybody else has tried that ...

anyway i figured ruger set the barrel-block clearance and then chambered and then added the barrel gadgets on the R1 ...

i will check the block flop in my 2 R1 actions and let you know.

i do remember F. DeHaas mentioning he would have like ruger to have less space between the block and barrel breech.

ken

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mashburn posted this 22 September 2020

Hello to all of you people with lead burns on your hands and wrists

I've got back to playing with the Ruger No.1 in .300 Win. Mag. I checked about 30 new cases in the chamber and with a feeler gauge I have determined the head space is .004". I'm going to form some cases that fit and shoot it some before contacting Ruger. If it shoots well, I'll just leave it as it is, if it don't shoot well I'll contact Ruger.

I've been out in the shop earlier tonight loading some cartridges. I'm seating the bullets out to touch the lands enough to push the case head back against the breech block. The loads that I am using for the fire forming are as follows. I'm using .170 gr. jacketed Sierra 30-30 bullets and 170 gr. cast gas checked bullets that have been powder coated. I may be going the wrong direction as far as my powder selection, but I have had such good luck with the Reloader series of powders in numerous calibers and rifles, that I am using  Reloader 7 and Reloader 22. I'm starting the jacketed bullets about 1 gr over suggested starting loads with Rel 7 and the gas checked powder coated cast bullets about 1.5 grs above suggested starting loads of Rel 22. I figure the cast bullet won't generate as much pressure so I upped the charge a little to hopefully blow the shoulder forward. The gas checked powder coated cast bullet is a bore rider and it fits the bore of the rifle perfectly. My main interest is to work up accurate loads. I only desire to develop accurate hunting loads. I'm not a paper puncher but i want my hunting rifles to have target accuracy. I've talked to several powder coaters who have convinced me that you can zip a properly gc'd powder coated bullet at jacketed bullet velocities. I've had a lot of PM's with our Norwegian member, Spindrift.

Years ago I was loading 30-30 bullets in my 30-06's. That was in my destitute days and couldn't afford a chronograph but by looking at the different charges and velocities given in the load books I was trying for about 2500 to 2600 fps. All that I can tell you is those things would literally drop a whitetail in their tracks. As time went by and my money became  more available, I quit playing with such. That is what I want to do with this .300 Mag. If I can accomplish this I will do some deer hunting with this rifle this fall. It seems like every season that I go in the deer woods with a new rifle, I harvest a trophy buck. I guess the deer have spread the word that all of my rifles are deadly. I guess I will never get too old to experiment and play with firearms. It's raining today and we are forecasted to get 3-4 inches of rain tomorrow, so i won't be shooting for a few days.

Mashburn

David a. Cogburn

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Spindrift posted this 23 September 2020

Mashburn; please keep us posted on your results. Good luck with your shooting and hunting!

The annual moose hunt is drawing near for me. I have actually never hunted with cast bullets before. I simply never had a rifle with a cartridge I considered adequate for moose with cast bullets. But now I have a .35 Whelen, which shoots very well with powder coated 310grs FP bullets (CBE360-300). My load is 47grs Vihtavouri N-150. The load is powerful, accurate and displays deep penetration with controlled expansion in water. 3 more days of waiting!

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mashburn posted this 23 September 2020

Hello Spindrift,

Was glad to hear your response. Moose is one thing that I don't have to hunt, sure wish I did though. I, like you have never hunted with cast bullets, matter of fact cast bullets in rifles is just a last couple of year adventure for me. I've shot a lot of soft lead projectiles in hunting with black powder rifles. I've shot cast in big bore revolvers for about 40 years and have pretty well mastered that skill. I've been shooting some powder coated bullets in my revolvers and have really had good luck with them. Until I discovered the Cast Bullet Association, I had only played a little with cast for rifles. I loaded a lot of cast, when my boys were young, to keep them supplied with ammo and not go broke doing so. 

I have several big bore rifles that are capable of taking big game. I have cast hunting loads worked up for my .375 Cogburn that I plan on taking a deer and some hogs with  this fall. The loads are gas checked hard lubed  bullets. They are very accurate but lead a little after several firings, but that is no problem with a hunting rifle.  I plan on working up some 280 grain powder coated gas checked loads up for it in the near future. I hope this .300 Win. Mag. project turns out to be a success, I have always liked Ruger No, 1's. 

Your .35 Whelen rifle intrigues me and I hope to hear more of your Moose hunting success with it. I have a .358 barrel blank in 1-16 twist that I'm going to build something on, either a .358 Win. or a .35 Whelen. I build my own rifles so I can afford to do much more rifle building than I would if I had to pay for the crafting. I've had a .458 American under construction for a couple of years (i got side tracked working on other projects) . I think that caliber would be a good rifle to shoot cast bullets. I'll keep you posted on the .300 project and I wish you the best of luck on your Moose hunt and keep me informed., Wish I was there to join you

Good luck again and thanks for all the helpful information that you have given me on powder coating and shooting,

Mashburn. 

David a. Cogburn

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