7mm Remington Mag load question

[Kuyong_Chuin]

My brother wants me to work up some loads for his 7mm Remington Mag rifles, yes plural he has two one savage and one ruger I think, anyways this is what he has, federal #215 large mag rifle primers, Lee RGB rifle die set, #5 shell holder, 70 empty cases, and 50 Nosler 150 grain Ballistic Silvertips. For powder he has H4831. So I went to Noslers website and loaded at their data for that bullet but it doesn't list H4831 there but it does list H4831SC that starts at 61 grains and max at 65 with 61 being the most accurate. So do I use the SC data for that bullet or do I use the jacketed data that the Lee manual list for H4831 starting load at 59 and max at 62? Lee manual uses a non mag primer too I do believe. :banghead:

 

[steve4102]

Lee data is not their own, it is a copy-n-paste of the powder distributors data, in your case Hodgdon data.

Hodgdon did use a Mag primer to develop their data.
http://data.hodgdon.com/cartridge_load.asp

SC stands for Short Cut and is identical to regular 4831 as far as load data is concerned.

From Hodgdon.

H4831SC - Ballistically, this Extreme Extruded powder is the exact copy of H4831. Physically, it has a shorter grain size, therefore, the designation SC or short cut. The shorter, more compact kernels allow the powder to flow through the powder measures more smoothly, helping to alleviate the constant cutting of granules. With the smoother flow characteristics comes more uniform charge weights, while the individual grains orient more compactly, creating better loading density.

What do you do? You start at 59gr and work up. You can stop at 62gr or you can follow Nosler data and continue if you are sure that your loads are still withing safe pressure limits.

BTW, the "Most Accurate" loads listed in a manual mean very little if anything to you and your rifle.

 

[Kuyong_Chuin]

Lee data is not their own, it is a copy-n-paste of the powder distributors data, in your case Hodgdon data.

Hodgdon did use a Mag primer to develop their data.
http://data.hodgdon.com/cartridge_load.asp

SC stands for Short Cut and is identical to regular 4831 as far as load data is concerned.

From Hodgdon.

H4831SC - Ballistically, this Extreme Extruded powder is the exact copy of H4831. Physically, it has a shorter grain size, therefore, the designation SC or short cut. The shorter, more compact kernels allow the powder to flow through the powder measures more smoothly, helping to alleviate the constant cutting of granules. With the smoother flow characteristics comes more uniform charge weights, while the individual grains orient more compactly, creating better loading density.

What do you do? You start at 59gr and work up. You can stop at 62gr or you can follow Nosler data and continue if you are sure that your loads are still withing safe pressure limits.

BTW, the "Most Accurate" loads listed in a manual mean very little if anything to you and your rifle.

Thanks Steve.

 

[Kuyong_Chuin]

One other question while I am thinking about it. When they were sighting in one of the rifles, the savage I think I'd have to ask which one we had out that day, I noticed something that to me doesn't sound quite right. The rounds were factory rounds and after they shot the round they were just tossing them into the empty cloth bag I had there at the time. When I went to place the empty cases back into the ammo box that the live rounds came out of they wouldn't fit. The case had whole case had expanded almost 9 thousands of an inch larger than the factory rounds were new and the primers were flattened out more than I normally see after a rifle round is shot. Is this a normal thing with the 7mm Remington Mag and belted mag cases?

 

[Reloadron]

The 7mm Remington Magnum cases will come out of the chamber sized according to the chamber they were fired in less about .001". The link shows you the acceptable cartridge dimensions for new factory ammunition as well as chamber dimensions.

My Ruger Model 77 doesn't change the cases much at all but that really means nothing. I assume when you say .009" change you mean the cartridge length? would be nice to know some numbers. Measure the cartridge overall length and look at the SAAMI specification in the link. I don't know what your case length was before being fired?

My Remington factory ammunition I have sitting here comes in at about 2.490" cartridge overall length. My once fired brass comes out of the rifle at about 2.491" to 2.492", just means I have a tight chamber in the Ruger.

Ron

 

[Reloadron]

Sorry I forgot to address this:

primers were flattened out more than I normally see after a rifle round is shot

On the ammunition I have here which is 10 spent and 10 new rounds in the same 20 round box the new cases have the primers sitting about .003" below flush with the case heads. The spent rounds come up flush with the case heads.



Not sure how you define "Normally"? Looking at the above image does what you have look anything like what I have? I consider what is in the image to be perfectly normal.

Ron

 

[steve4102]

Flattened primers is most often caused by excess headspace and not excess pressure. Reading primers to determine pressure is A Kin to reading tea-leaves.

 

[Kuyong_Chuin]

The 7mm Remington Magnum cases will come out of the chamber sized according to the chamber they were fired in less about .001". The link shows you the acceptable cartridge dimensions for new factory ammunition as well as chamber dimensions.

My Ruger Model 77 doesn't change the cases much at all but that really means nothing. I assume when you say .009" change you mean the cartridge length? would be nice to know some numbers. Measure the cartridge overall length and look at the SAAMI specification in the link. I don't know what your case length was before being fired?

My Remington factory ammunition I have sitting here comes in at about 2.490" cartridge overall length. My once fired brass comes out of the rifle at about 2.491" to 2.492", just means I have a tight chamber in the Ruger.

Ron

No I was not talking about the length, I was talking about the diameter of the case at the belt. The case measurement on the unfired case is 0.513 on the fired case it is 0.5195 on the one I just pulled out and measured. When they was still warm from firing they was 0.522 at the case belt. Right now they are pretty cold since they were in an unheated area of the basement. He said it was the Ruger Model 77 that they were shooting.

Not sure how you define "Normally"? Looking at the above image does what you have look anything like what I have?

There is less of a gap on these than the fired case in the picture. They are flush with the edge of the primer pocket and no bevel left on the primer. I'll try to remember to take a picture of one when I get my batteries for my camera charged back up.

 

[gamestalker]

I don't have my load books, or my log books in front of me at the moment. But over the last year or so I've been using a lot of H4831 and it has performed very well in comparison to RL22 which has been my #1 powder for years. I have found the preferred sweet spot at the upper end of the table to be best suited for our shooting needs, which is primarily hunting. For putting holes in paper I would very likely go with an accurate load some where around mid table or slightly less. Just don't take it too far down the table or you'll start to have low pressure issues.

As for reading primers, it's an unreliable method of making pressure determinations, unless you already have a base line knowledge of how each primer brand looks when it is known to be experiencing excessive pressures. And to add to the issue, Federal primers are known to be softer than Win and CCI. Probably the best pressure guide in this respect would be bolt lift, and chrony results, with bolt lift being a much better indicator.

As far as the diameter of the brass post firing, I would say it has something to do with a loose chamber. Speaking of brass, are you separating the brass according to the firearm it was fired from? If not, you'll have some issues when resizing, as in shoulder bump.

GS

 

[witchhunter]

Agree with gamestalker, you should separate brass for each rifle. Treat each one as a different caliber, meaning different sizing and seating adjustment. In the calibers that I have multiple rifles, I have a seperate set of dies for each. Pistols no, rifles, bolt action, yes, as I am shooting for accuracy with them.

 

[Reloadron]

No I was not talking about the length, I was talking about the diameter of the case at the belt. The case measurement on the unfired case is 0.513 on the fired case it is 0.5195 on the one I just pulled out and measured. When they was still warm from firing they was 0.522 at the case belt. Right now they are pretty cold since they were in an unheated area of the basement. He said it was the Ruger Model 77 that they were shooting.

OK, I assumed, wrongly, case length.

The belt diameter should be .532" -.005" or a minimum of .527" and a maximum of .532" My unfired new Remington ammunition is .527" and my once fired in my rifle is out at .527" and that is at room temperature of about 70 degrees F. That is the rim OD. The case OD at .250" up from the case head base should be around .5127" or call it .513". Would that be where you are measuring? Max chamber .250" up from the base should be .5136" and that is chamber not cartridge so if a chamber is in specification no brass leaving it should exceed about .001" less than that.

These dimensions are all called out on the SAAMI drawing I linked to earlier. I see where the primer has been covered and a good picture or two will help.

Also as mentioned it is unwise to mix the brass if you are planning to neck size only for a bolt gun. Each rifle unto its own brass.

Ron

I am guessing this is factory new ammunition we are looking at and not hand loads? I see the plan for hand loads but am unsure if these were hand loads or factory new?

 

[Kuyong_Chuin]

OK, I assumed, wrongly, case length.

The belt diameter should be .532" -.005" or a minimum of .527" and a maximum of .532" My unfired new Remington ammunition is .527" and my once fired in my rifle is out at .527" and that is at room temperature of about 70 degrees F. That is the rim OD. The case OD at .250" up from the case head base should be around .5127" or call it .513". Would that be where you are measuring? Max chamber .250" up from the base should be .5136" and that is chamber not cartridge so if a chamber is in specification no brass leaving it should exceed about .001" less than that.

These dimensions are all called out on the SAAMI drawing I linked to earlier. I see where the primer has been covered and a good picture or two will help.

Also as mentioned it is unwise to mix the brass if you are planning to neck size only for a bolt gun. Each rifle unto its own brass.

Ron

I am guessing this is factory new ammunition we are looking at and not hand loads? I see the plan for hand loads but am unsure if these were hand loads or factory new?

Factory new rounds, all fired in the Ruger Model 77. The Savage has not been fired yet it is having a scope installed. Was measuring the case just in front of the belt of the case. I'll grab a case and give a full set of measurements here in a few minutes. Have to do something with the 15 month old girl that won't let me sit her down first.

Case length 2.5135 , 0.4975 at start of shoulder, belt is 0.5325, just below the belt 0.5165, case neck 0.320 wall thickness 0.0140

A couple of the better rounds.

 

[Kuyong_Chuin]

Bump

 

[Reloadron]

Your numbers for a fired case don't look that bad to me. They seem to be a little high but in specification for SAAMI. The spent primers look fine. They look like they had a factory crimp that none of my new stuff does but my new stuff is well over 10 years old.

Before I forget, loved the part about the 15 month old.

I would size them and load them.

One more note. If you can use them and want them for comparison I can send you an empty box (20 cases) as I have buckets of 7mm Rem Mag. I don't want anything for them so let me know if you can use them.

Ron

 

[Kuyong_Chuin]

Sure could use them. Thanks. On the 15 month old she can be a hand full now that she is walking but I don't know what I would do without her here. Was sitting at the bench the other day trying to figure out a way stabilize it more till I can build it up and she was sitting on my lap and started to work the press handle pulling it all the way down and back up. She is a smart little girl and she already tries to play my Uke. She holds it right and strums it. When she gets older I'll teach her how to play it right.

 

[nastynatesfish]

The cases are going to expand. When you size just size it enough to chamber easy. Don't try and get it back to spec. My 7mag I have some brass with 20 loads on them. I run 64gr h4831sc with a 140 Berger and 63.5gr h4831 with a 162 amax. Neither is hot and I have no pressure issue at all. If idout loosen the barrel nut on the savage. Have a new case or a proper full length sized on and chamber. The UNLOADED case. Screw the barrel down untill you feel it start to get tight. Back it up till its just snug and tighten down the nut. I do all my savages that way. You'll tighten up the headspace a bit and your brass won't strecth so much. You cannt use same load in both rifles so make sure you keep them separate. Best way is to use different bullets in each and label label label you ammo boxes

 

[nastynatesfish]

Oh and I never use mag primers in mine.
Here's my target from my load

Work the aol on that 64gr charge and I'm sure it'll shoot fine

 

[Reloadron]

Sure could use them. Thanks. On the 15 month old she can be a hand full now that she is walking but I don't know what I would do without her here. Was sitting at the bench the other day trying to figure out a way stabilize it more till I can build it up and she was sitting on my lap and started to work the press handle pulling it all the way down and back up. She is a smart little girl and she already tries to play my Uke. She holds it right and strums it. When she gets older I'll teach her how to play it right.

Got your PM. Give me a few days to get a padded mailer and I'll send those cases. They may help you out. They are once fired in my Ruger. Wish this arctic weather would go away.

Ron