First time loading 300 WM - Questions

[MMH]

I am beginning to work up loads for a 300 WM. This will be my first time loading a belted magnum. The rifle is a Remington 700 Long Range and has a 26” barrel w/ a 1:10 twist and a deep throat. I have allot of once fired brass (mostly R-P & Barnes). This brass will chamber in my rifle w/o sizing (although there is some force required to close the bolt handle. Anyway, here are the steps that I am intending to follow.

• -Size the neck w/ a Lee collet die. I will use the standard diameter decapping rod.
• Size w/ Redding body die. Adjust die such that bolt will close (on empty case) w/ a very slight drag. Eventually I will get a Larry Willis collet die but don’t have one now.
• Clean/Uniform primer pockets, chamfer necks from inside/outside & prime the cases. Should the primer be a magnum primer or standard? I heard that standard primers result in a lower SD.
• Starting loads will be 72 gr. H1000 & 74 gr. Retumbo. Each load will be individually weighed.
• Hornady 212 gr. ELD-X bullets will be loaded & be seated w/ a Forster micrometer seating die to where the bullet is 0.020” off of the lands. The rifle has pretty long freebore & this will result in a COAL of approximately 3.59”.

I will only load 3 rounds of each. If cases are OK will go up by 0.5 grains on both powders & load 3 more of each powder. Will continue to do this until I get to a max load (looking at primers & extractors for pressure signs).

Is my intended procedure correct? Any other words of wisdom?

 

[fguffey]

I am beginning to work up loads for a 300 WM. This will be my first time loading a belted magnum. The rifle is a Remington 700 Long Range and has a 26” barrel w/ a 1:10 twist and a deep throat. I have allot of once fired brass (mostly R-P & Barnes). This brass will chamber in my rifle w/o sizing (although there is some force required to close the bolt handle. Anyway, here are the steps that I am intending to follow.

I see no reason for you to purchase a Larry Willis collet die. I suggest you measure before and again after.

F. Guffey

 

[XBBR Shooter]

I am beginning to work up loads for a 300 WM. This will be my first time loading a belted magnum. The rifle is a Remington 700 Long Range and has a 26” barrel w/ a 1:10 twist and a deep throat. I have allot of once fired brass (mostly R-P & Barnes). This brass will chamber in my rifle w/o sizing (although there is some force required to close the bolt handle. Anyway, here are the steps that I am intending to follow.

• -Size the neck w/ a Lee collet die. I will use the standard diameter decapping rod.
• Size w/ Redding body die. Adjust die such that bolt will close (on empty case) w/ a very slight drag. Eventually I will get a Larry Willis collet die but don’t have one now.
• Clean/Uniform primer pockets, chamfer necks from inside/outside & prime the cases. Should the primer be a magnum primer or standard? I heard that standard primers result in a lower SD.
• Starting loads will be 72 gr. H1000 & 74 gr. Retumbo. Each load will be individually weighed.
• Hornady 212 gr. ELD-X bullets will be loaded & be seated w/ a Forster micrometer seating die to where the bullet is 0.020” off of the lands. The rifle has pretty long freebore & this will result in a COAL of approximately 3.59”.

I will only load 3 rounds of each. If cases are OK will go up by 0.5 grains on both powders & load 3 more of each powder. Will continue to do this until I get to a max load (looking at primers & extractors for pressure signs).

Is my intended procedure correct? Any other words of wisdom?

("This brass will chamber in my rifle w/o sizing (although there is some force required to close the bolt handle.)"

If you can close the bolt with force, then do not use a body die - neck size it and shoot it and the case will form to YOUR chamber.

As Guffey said, don't waste time with the Willis die (I can't believe I agreed with Guffey )

The 300 WM is a pussy cat to load for.

If you feel that after the first firing, the bolt closes with too much force, get a Forster Bump die, and use it sparingly.

If you learn nothing else, remember that the 300 WM (and all of it's belted cousins) use the belt for head space, FOR THE FIRST FIRING only... after that, it uses the shoulder for headspace control - and it is sooooo easy to over size belted cases.

If the base/web expands enough to interfere with chambering or extraction, then get a small base FL die (RCBS and Redding make them) and size just enough to remove the resistance - but DO NOT push the shoulder back - you will get head separations in a New York minute.

 

[Steve Blair]

If you learn nothing else, remember that the 300 WM (and all of it's belted cousins) use the belt for head space, FOR THE FIRST FIRING only... after that, it uses the shoulder for headspace control - and it is sooooo easy to over size belted cases.

How about the .458 Winchester Magnum? Does that use the shoulder?

 

[XBBR Shooter]

How about the .458 Winchester Magnum? Does that use the shoulder?

Cute... it has no shoulder.

 

[Zero333]

I don't like Remington brass for my 300winmags, broke 2 decapping pins cause of it.... Off center flasholes.

 

[Steve Blair]

Cute... it has no shoulder.

So, not quite "all of it's [sic] belted cousins".

 

[XBBR Shooter]

So, not quite "all of it's [sic] belted cousins".

That is so cleaver. How long did it take you to come up with that?

 

[Steve Blair]

That is so cleaver [sic]. How long did it take you to come up with that?

Probably less than your original, erroneous post. At least one belted cartridge, from the same manufacturer, does not headspace on its (nonexistent) shoulder.

 

[bozo699]

("This brass will chamber in my rifle w/o sizing (although there is some force required to close the bolt handle.)"

If you can close the bolt with force, then do not use a body die - neck size it and shoot it and the case will form to YOUR chamber.

As Guffey said, don't waste time with the Willis die (I can't believe I agreed with Guffey )

The 300 WM is a pussy cat to load for.

If you feel that after the first firing, the bolt closes with too much force, get a Forster Bump die, and use it sparingly.

If you learn nothing else, remember that the 300 WM (and all of it's belted cousins) use the belt for head space, FOR THE FIRST FIRING only... after that, it uses the shoulder for headspace control - and it is sooooo easy to over size belted cases.

If the base/web expands enough to interfere with chambering or extraction, then get a small base FL die (RCBS and Redding make them) and size just enough to remove the resistance - but DO NOT push the shoulder back - you will get head separations in a New York minute.

Bwahahahahaha!!!!!!

 

[MMH]

Thanks for all the replies. So based on these replies here are my thoughts for a modified procedure:

• Check to see if bolt will close on previously one-fired cases (even is some force is required on the bolt).
• Size the neck w/ a Lee collet die. I will use the standard diameter decapping rod.
• Verify that max. case lentgth of 2.620" is not exceeded.
• Clean/Uniform primer pockets, chamfer necks from inside/outside & prime the cases.
• Starting loads will be 72 gr. H1000 & 74 gr. Retumbo. Each load will be individually weighed. Load three rounds of each powder at starting load and then increase weight by 0.5 gr. & load three rounds of each & continue to increment to to final weight of 78.0 gr. of H1000 & 81.0 gr. of Retumbo. Thus will have 39 rounds of H1000 & 45 rounds of Retumbo loaded.
• Hornady 212 gr. ELD-X bullets will be loaded & be seated w/ a Forster micrometer seating die to where the bullet is 0.020” off of the lands. The rifle has pretty long freebore & this will result in a COAL of approximately 3.59”.
• Go to range and shoot at 100 yards. Even though rifle not shot yet, shoot to determine OCW. At each charge weight inspect case looking for signs of excessive pressure.

Comments please!

 

[fguffey]

Comments please!

I see no reason for you to purchase a Larry Willis collet die. I suggest you measure before and again after.

Thanks for all the replies. So based on these replies here are my thoughts for a modified procedure:

Again: I was asked to form belted cases for a wildcat chamber. The builder of the rifles would have formed them himself if it was easy; so he called me and I had to determine if it was possible. After that I boxed up my dies and went for a visit, the last thing he requested was 'the other #4 shell holder'. I did not have to sort through 440 belted cases to determine which cases would fit my #4 shell holder because he had already done that. After forming the 400 belted cases we started on the 40 'that required a special shell holder'. I used a small case friendly hammer to drive the cases into my shell holder and that got his attention. I suggested if the case will not fit the shell holder determine why; I knew these cases had been hammered with heavy loads. I suggested we measure the diameter of the case head at the bottom of the extractor groove. the case head had expanded .011". There was no reason for me to measure the diameter of the case in front of the belt because I knew it got hammered when the case head got hammered. We measured; the case in front of the belt had expanded .008". He wanted to know how to fix the hammered cases; I suggested he use one of his lathes with a collet if he was that desperate. He decided against it. He could have cut the extractor groove or modified a shell holder or find himself a case friendly hammer. Problem: The cases he was forming were to be used with the rifles he was building.

Will continue to do this until I get to a max load (looking at primers & extractors for pressure signs).

Why would you do that? What are you looking for? Accuracy or trying to determine what happens when a case head gets hammered?

Measure before and again after before firing and again after. I know it is acceptable to look for signs of high pressure, I have a flash hole diameter gage, if the diameter of the flash hole increases the diameter of the case head increases and the primer pocket gets loose and the case no longer fit my shell holders. I have a set of shell holders that are unforgiving, if a case fits the shell holder and fails to fit after firing the case head got hammered. Some shell holders fit better than others, there is more utility in a shell holder that only fits where it touches.

my thoughts for a modified procedure:

Measure before and again after firing.

F. Guffey

 

[MMH]

So when you say measure, I presume that you mean measure right above the belt. How much expansion is acceptable.

I am not trying to hammer the cases or develop a super hot load. I am interested in finding the accuracy node, so, as long as the case is not getting hammered I want to start w/ a low charge & go up to the maximum (safe) charge.

Other than measuring the cases, does my modified procedure look OK?

 

[XBBR Shooter]

Other than measuring the cases, does my modified procedure look OK?

Yes...

 

[MMH]

I see no reason for you to purchase a Larry Willis collet die. I suggest you measure before and again after.

F. Guffey

I've measured a bunch of my cases and they are at 0.512" - 0.513" just in front of the belt. After firing, how much can they expand before indicating excessive pressure?

 

[XBBR Shooter]

I've measured a bunch of my cases and they are at 0.512" - 0.513" just in front of the belt. After firing, how much can they expand before indicating excessive pressure?

That area is not the place that warns of pressure - pressure is noted by primer signs and ejector marks and/or ejector wipes.

SAAMI minimum (for new cases) for that area is 0.5118" and max is 0.5126", so your fired cases are well within comfort zone.

Don't worry, enjoy the 300 Win Mag.

 

[Berger.Fan222]

Seems like a good approach.

I would stop increasing the charge when you find an accurate load with "enough" velocity, which for me means 2850ish in that weight range.

Pushing the pressure will wear out your brass more quickly and make it harder to find an accurate load.

When I find a load that is fast enough and shows promising accuracy, I try three different OALs, often one a bit longer and one a bit shorter than my starting OAL. The .300 WM I am working with now likes the 208 ELD about 0.060" from the lands with 74 grains of H4831 for 2850 fps from a 26" barrel.

 

[MMH]

That area is not the place that warns of pressure - that is in front of the web.

SAAMI minimum (for new cases) for that area is 0.5118" and max is 0.5126", so your fired cases are well within comfort zone.

Don't worry, enjoy the 300 Win Mag.

I am confused - what is the area "in front of the web" and what should that dimension be?

 

[fguffey]

I've measured a bunch of my cases and they are at 0.512" - 0.513" just in front of the belt. After firing, how much can they expand before indicating excessive pressure?

I purchased a Winchester Model 70 with a 300 Win Magnum chamber. After firing I did not have a die that would fit the case; I have small base 300 Win Magnum dies, forming dies and full length sizing die with neck sizers. I called Winchester, Winchester sent me ‘to their Warranty man’. I explained to him their chamber was the ugliest I have ever seen; it was too long from the shoulder to the bolt face and too large in diameter. Long story, he reamed, polished and honed, when finished the chamber was uglier. I was thinking I needed to get out of that place with my rifle when he informed me he sent the rifle back to Winchester. And then it did not get better.


I have no ideal what went wrong; I believe Winchester did. When I purchase a new rifle I should get a new rifle. I have no infatuation with head space gages but if I did I would have taken the cases that would not fit the shell holder and cut them off.200” in front of the belt. Cutting the case off ahead to the bulge would eliminate the case body and shoulder as being the cause of difficult to size.


In the beginning what ever happened in front of the belt when the case was fired was not considered important. By design the case body was designed to fill the chamber, if the belt held the case to the rear the shoulder had nothing to do. And if the belt worked the shoulder did not move but that is something reloaders can wrap their minds around.


F. Guffey

 

[XBBR Shooter]

I am confused - what is the area "in front of the web" and what should that dimension be?

Today is my day for 300 WM pictures..