Variation in initial/max weights for reloading manuals

[WVmike]

I've been reloading for about a year now, mainly .308 and 7mm Rem Mag and I have noticed that there is a big difference between manuals in initial grain weight and the maximum weight. I have a lyman (previous year edition) and nosler (not sure off the top of my head what edition). I use mainly the lyman manual but was comparing the two the other day and noticed a pretty substantial difference in initial/max weight difference in the .308. 150 gr bullet for lyman, initial weight was 42.0 gr and I believe 46.0 gr for nosler. My question to those that have been reloading longer than me is what is the variation from? Is it the receiver they use (universal vs actual barrel action/barrel length, etc) or is it just the brand variance? I would rather not have my rifle explode in my face when tinkering with loads. I understand to look for pressure differences, COAL, etc but was just curious. Thanks for any input.

 

[littlebighorn]

I'm sure it has to do with the rifles and tolerances they are testing with, as well as many other variables that come into play with load development. (legal liability, etc.)
I have always felt any published starting load is pretty safe, and from there you have to determine what works in your rifle. I think the most critical factor for you to be safe is to learn how to read pressure signs in your set up. Your rifle will be different than most any other, brass thickness, primer make, etc. etc. all contribute.
If you are only into it a year, I'd stay on the safe side. I always look at my brass for signs of too much pressure. I found this link to be helpful.

Understanding Pressure :: Primal Rights, Inc

Reading pressure is a required skill that all shooters must have. Whether you are shooting factory ammunition or your own handloads, you absolutely must be able to detect and interpret pressure signs on your fired brass.

www.primalrights.com

 

[WVmike]

I'm sure it has to do with the rifles and tolerances they are testing with, as well as many other variables that come into play with load development. (legal liability, etc.)
I have always felt any published starting load is pretty safe, and from there you have to determine what works in your rifle. I think the most critical factor for you to be safe is to learn how to read pressure signs in your set up. Your rifle will be different than most any other, brass thickness, primer make, etc. etc. all contribute.
If you are only into it a year, I'd stay on the safe side. I always look at my brass for signs of too much pressure. I found this link to be helpful.

Understanding Pressure :: Primal Rights, Inc

Reading pressure is a required skill that all shooters must have. Whether you are shooting factory ammunition or your own handloads, you absolutely must be able to detect and interpret pressure signs on your fired brass.

www.primalrights.com

I appreciate the info. I found that 42.5 gr of Varget with 150 Hornady SST give me under 1 moa and even 3/4 moa if I do my part. I was just curious as to why such the huge difference.

 

[homers]

Different guns, brass, etc.

 

[std7mag]

Different receiver, different barrels, different barrel lengths.
Add in different primers, different cases, different lots of powder, different bullets.

If you get online, some bullet & almost all the powder manufacturers have data for their components.

You could also download Gordon's Reloading Tool.
Predictive software.
Or buy Quickload/Quicktarget.

 

[Wind Gypsy]

Which brass is used, powder lot, and primer probably make the biggest difference but lots of things play into it.

 

[Wind in His Hair]

Yeah some brass is going to be thicker and have less case capacity vs thinner will have more, etc. Dont start at max.

If you have a new rifle I'd start somewhere in the middle of the range, if you have an older rifle I'd start at the bottom of the range

 

[BRI]

I've only been reloading 10 years now and no expert by any means but I've reloaded for 12 different guns now and feel I have a pretty good understanding. This year while I was doing some testing with 90 grain Hornady CX bullets and H4350 in my 243. I looked at Nosler, Barnes, Hodgdon, Hornady sites and noticed quite a bit of discrepancy between the min/max. I chose my starting load in the mid range which was a lower charge than I was currently using with the 90 grain eldx. First shot I could tell was way hot immediately at the shot, bolt hard to lift, primer pocket blown and split case. I pulled bullets and then dropped 2 grains, loaded a few more. First shot same results, sticky bolt, blown primer, split case. Dropped 2 more grains loaded a few more and was still a hot load. I stopped testing that combo at that point and stuck with the eldx. That's really been my only WTF moment in reloading so far.

 

[cahunter805]

I've only been reloading 10 years now and no expert by any means but I've reloaded for 12 different guns now and feel I have a pretty good understanding. This year while I was doing some testing with 90 grain Hornady CX bullets and H4350 in my 243. I looked at Nosler, Barnes, Hodgdon, Hornady sites and noticed quite a bit of discrepancy between the min/max. I chose my starting load in the mid range which was a lower charge than I was currently using with the 90 grain eldx. First shot I could tell was way hot immediately at the shot, bolt hard to lift, primer pocket blown and split case. I pulled bullets and then dropped 2 grains, loaded a few more. First shot same results, sticky bolt, blown primer, split case. Dropped 2 more grains loaded a few more and was still a hot load. I stopped testing that combo at that point and stuck with the eldx. That's really been my only WTF moment in reloading so far.

The CX is an all copper mono bullet. It will require the load to be less powder vs a bullet of the same weight in lead. Also most people start at about .050 from the lands.

 

[MThuntr]

I've only been reloading 10 years now and no expert by any means but I've reloaded for 12 different guns now and feel I have a pretty good understanding. This year while I was doing some testing with 90 grain Hornady CX bullets and H4350 in my 243. I looked at Nosler, Barnes, Hodgdon, Hornady sites and noticed quite a bit of discrepancy between the min/max. I chose my starting load in the mid range which was a lower charge than I was currently using with the 90 grain eldx. First shot I could tell was way hot immediately at the shot, bolt hard to lift, primer pocket blown and split case. I pulled bullets and then dropped 2 grains, loaded a few more. First shot same results, sticky bolt, blown primer, split case. Dropped 2 more grains loaded a few more and was still a hot load. I stopped testing that combo at that point and stuck with the eldx. That's really been my only WTF moment in reloading so far.

you're going to need to back way off and start at the beginning. As Cahunter mentioned, it's a hard copper bullet that will generally require a lower starting load and more jump.

Blown primers can cause some issues, damaging the firing pin and cause bolt face etching. A damaged firing pin can cause pierced primers compounding the issue. You're going to want to inspect the rifle.

 

[BRI]

The CX is an all copper mono bullet. It will require the load to be less powder vs a bullet of the same weight in lead. Also most people start at about .050 from the lands.

Thanks. I'm aware of that and have switched to all copper in seversl other guns. Currently using 150 grain cx in my 280AI after using Hammers for 4 years. In the 280AI I started at min load with no issues. With the 243, the last load was 2 grains below book minimum and still over pressure, so that's what was most surprising.

 

[JT88]

Another easily overlooked issue is the difference in bullet designs of the same weight. For example, a flat base bullet can potentially take up more combustion space in the case than a boat tail, or vice versa, depending on seating depth. So with everything else being equal, this will cause a higher pressure, even though the bullets weigh the same amount

 

[44hunter45]

A change in bullet means finding the lands and seating depth all over again. This means backing down and working up.
I ran into a KDF Kleingunther rifle in 7mm that could never shoot heavier than 145 grain anything because the throat was so short.

Monolithic bullets are longer than lead, so they take up more of the available powder capacity for the same relative COAL. As mentioned above, boattail bullets also take up more space. I like my start loads to be at least 70% case fill. Too low a start charge is just as dangerous as too high.

I absolutely nerd out on this stuff. It's part of the process for me. With a scale and caliper you can work out any number of ways to approximate case capacity or percentage of fill.

After I figure out where the lands are for this bullet and rifle, I find the heaviest piece of brass in the lot and seat the bullet to depth without a primer. I weigh that. I syringe distilled water into the case until it is full and weigh it again. The difference is the actual case capacity in grains of water. I set up the cartridge and bullet with my seating data in QuickLoad and adjust the overall case capacity variable until the numbers match. I find this gives me very accurate load density values in QuickLoad.

There are other sanity checks you can do. I used to mic the case with the probe on my caliper and find the web to case mouth distance. Then case mouth to the bottom of the shoulder. Subtract to get web to shoulder distance. I would probe the height of my start charge in a standing case, subtract from previous number to get a general idea of the load density. This is not a highly accurate method, but it will keep you above your minimum charge. It does not account for the capacity lost to the seated bullet.

At the very least, give your start loads a shake and make sure you hear powder rattle in there. For certain powders you could theoretically have a high density start load, but it would not be the norm.

 

[Don Fischer]

I use different manuals quite a bit when I find a powder I want to use with a certain weight bullet. Trick is first check for pressure. I load one round each of the different data starting at starting load in the manual I'm using and work up to one grain over max. After each round I look for pressure signs, sticky bolt, badly flattened primer, extractor mark on the case head and soon as I get one I stop and consider it max. Then I start from a couple grains below that and start working up. The problem with data like you are questioning has to do mostly from the different rifle and the altitude so I've read. But if you look you'll find the data has equal data somewhere along the line. So create your own data. Sort of like going from a 130gr bullet down to 125gr bullet. Start low with the 130gr load and work your way up. Or start low with the 125gr bullet and 130gr data and again work your way up.

Work on recognizing pressure sign's and if your just not getting, stay with the bullet manufacturer's load data. The only Lyman book I have is for cast bullet loading but I always hear good about it. And I have an old Hodgdon's book that has also server me well, neither make bullet's!

Word of caution using belted mag cartridges and slow powder's. Start about one grain over the starting load. Problem as it was explained to me was light loads on slow powder in a belted case, the spark jumps the powder and burns backward increasing pressues badly. You can feel it and with the muzzle pointed down the powder settle's in the front of the case leaving a gap between the flash hole and back of the powder. I have no idea how the spark would jump the powder like that but that's what I was told. Point the same rifle with the same load up and the powder settle's on the flash hole, problem goes away and I've done that and it does work.

One other problem with belted mags is many have sloppy chamber's. Comes from head spacing on the bely rather than the neck. To avoid the problem, neck size with an FL die and shoot till the case will no longer chamber, get's to big blowing out the shoulder. When you reach that point, start moving the FL die toward the shoulder maybe 1/4 turn at a time and checking to see if it will chamber. Word of caution, case fit's when you can no longer feel restraint of the case wen closing the bolt. What you have done is move the head spacing tp the shoulder. Over the years I started doing this with all my case's regardless where the head spacing was. I found that in some cartridges of different caliber's I actually had a sloppy chamber. Last one I tried it on was a 243. Ended up with two at the same time. the rounds for one would not let the cartridge chamber in the other and rounds for the other worked in both! Difference in chamber dementions I believe. These days if I get a rifle in a cartridge I already have I also get a new set of dies and each rifle has a die set up for that particular chamber!

Got a little carried away here, sorry. Bottom line learn to read pressure signs and you can swap manuals but keep the bullet weight's the same. As for monolithic bullet's I've never loaded for them and I would be very cautious. As I understand it the bullet's are made from different metals. Few company's make them from gilding metal and at least one other from pure copper. I would suspect the difference's could change the pressure even with the same charge's.

 

[WVmike]

I use different manuals quite a bit when I find a powder I want to use with a certain weight bullet. Trick is first check for pressure. I load one round each of the different data starting at starting load in the manual I'm using and work up to one grain over max. After each round I look for pressure signs, sticky bolt, badly flattened primer, extractor mark on the case head and soon as I get one I stop and consider it max. Then I start from a couple grains below that and start working up. The problem with data like you are questioning has to do mostly from the different rifle and the altitude so I've read. But if you look you'll find the data has equal data somewhere along the line. So create your own data. Sort of like going from a 130gr bullet down to 125gr bullet. Start low with the 130gr load and work your way up. Or start low with the 125gr bullet and 130gr data and again work your way up.

Work on recognizing pressure sign's and if your just not getting, stay with the bullet manufacturer's load data. The only Lyman book I have is for cast bullet loading but I always hear good about it. And I have an old Hodgdon's book that has also server me well, neither make bullet's!

Word of caution using belted mag cartridges and slow powder's. Start about one grain over the starting load. Problem as it was explained to me was light loads on slow powder in a belted case, the spark jumps the powder and burns backward increasing pressues badly. You can feel it and with the muzzle pointed down the powder settle's in the front of the case leaving a gap between the flash hole and back of the powder. I have no idea how the spark would jump the powder like that but that's what I was told. Point the same rifle with the same load up and the powder settle's on the flash hole, problem goes away and I've done that and it does work.

One other problem with belted mags is many have sloppy chamber's. Comes from head spacing on the bely rather than the neck. To avoid the problem, neck size with an FL die and shoot till the case will no longer chamber, get's to big blowing out the shoulder. When you reach that point, start moving the FL die toward the shoulder maybe 1/4 turn at a time and checking to see if it will chamber. Word of caution, case fit's when you can no longer feel restraint of the case wen closing the bolt. What you have done is move the head spacing tp the shoulder. Over the years I started doing this with all my case's regardless where the head spacing was. I found that in some cartridges of different caliber's I actually had a sloppy chamber. Last one I tried it on was a 243. Ended up with two at the same time. the rounds for one would not let the cartridge chamber in the other and rounds for the other worked in both! Difference in chamber dementions I believe. These days if I get a rifle in a cartridge I already have I also get a new set of dies and each rifle has a die set up for that particular chamber!

Got a little carried away here, sorry. Bottom line learn to read pressure signs and you can swap manuals but keep the bullet weight's the same. As for monolithic bullet's I've never loaded for them and I would be very cautious. As I understand it the bullet's are made from different metals. Few company's make them from gilding metal and at least one other from pure copper. I would suspect the difference's could change the pressure even with the same charge's.

You guys are like an encyclopedia. Thanks for the info. Glad I joined the forum!

 

[elevatorman]

I use whatever publicly published accurate tested data is available, have a few different reloading magazines with lots of loads in the back. If there's a discrepancy on a certain load between books I use the one that let's me use more powder. Still start a little lower and work up looking for signs. To me reloading for my rifles is all about performance. I want the most juice I can squeeze outta it.

 

[elevatorman]

Don't read my above post as an advocate for irresponsible loading but that both books will have been published with pressure tested safe load data. I use the book with highest powder charge without concern, but do still keep safety in mind and check carefully for pressure signs.

Actually my 7mm rem mag loads .5 grains under book max. There was no velocity gained from .5 grain under to book max so I took the safer route.