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> Load Data : 7mm RM 162gr SST
Load Data : 7mm RM 162gr SST
@ 06:06 am (GMT) |
deerndingoHi All,I'm just checking my data before I load. I did some bench work with a 7mm RM, Rem700, 26". Loaded it with 162gr SST's in Sako brass and long rifle primers and a range of loads from 62 up to 70 grains. The total length of the loaded round is 2.470" (long throated). I kept the brass in order of load and checked for pressure signs. I found there was a faint sign of pressure (ejector ring polish on head) on the 70gr load. After a long break I decided to load up hunting loads today. I'm using magnum primers this time and taking one grain from the load to end up with 68grains Reloader 22. Being careful I just thought I'd check a few data points for load data just to check my numbers. I found the Alliant Powder site and Load From a Disk gives a max of 65grains and Nick Harvey gives 63 grains!!! I'm now concerned about my results because of what the other load data sources are telling me. A penny for your thoughts please. Thanks in advance for your comments. |
Replies
@ 07:40 am (GMT) |
jason brownRe: Load Data : 7mm RM 162gr SSTim no expert but the book powder values do seem light to what people actually use. so I wouldn't fear too much.in saying that a lot of us use adi 2217 or h1000 being the equivalent. and about 72 grains of it. but your powder might be hotter, im not sure. I guess, like your doing just keep an eye on pressure signs, and if none your good to go. try the 162 amax if you can get any. |
@ 06:49 pm (GMT) |
Nathan FosterRe: Load Data : 7mm RM 162gr SSTHi Danny, you are probably using much heavier walled brass than is typical for load work so you are possibly about right where you are. You may want to work up a touch hotter and observe bolt lift and primer pockets etc.I would have preferred that you started with U.S made brass and locally made 2217 powder for optimum temperature stability in Oz conditions. Nevertheless, what's done is done. |
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@ 02:47 am (GMT) |
deerndingoRe: Load Data : 7mm RM 162gr SSTThanks for those answersNathan, In terms of a heavy load, if the Sako is heavy brass then won't that be negated after the first firing and then reverting to neck sizing. |
@ 11:53 am (GMT) |
John SmithRe: Load Data : 7mm RM 162gr SSTIn my Ruger No. 1A in 7 x 57 I use the Hornady 162 A-Max bullet, WLRprimers, and either 45.5 gr. of IMR 4350 or 42.5 gr. of IMR 4064 in Norma cases. OAL 3.094". I don't see any sign of excess pressure on the cases after firing. Accuracy is good enough for me. 4064 powder is one of the powders now available here in eastern Washington. |
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@ 05:01 pm (GMT) |
Nathan FosterRe: Load Data : 7mm RM 162gr SSTHi Danny, no it will stay the same thickness throughout, even after fire forming and neck sizing. I have not used Sako 7mm Rem Mag brass so keep in mind that I am only making assumptions based on experience with the likes of RWS. The point being that some brands of European brass can be heavy walled and that this is possibly a limiting factor for you.A chronograph would be useful if you can get hold of one. |
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@ 11:27 pm (GMT) |
deerndingoRe: Load Data : 7mm RM 162gr SSTI ave a chrono. My point concerning toughness of brass was more regarding the buffer effect that FL sized thick brass can have on pressure curves. I have found that in my 22-250 I get a higher fps for same pressure signs using more powder in a FL sized case than a neck sized case using Nosler or Lapua brass.All that said, do you think the 68gr of Reloader 22 for about 3030fps sounds sough of right. It just reads so high compared to all the literature. I'm inclined to ignore the data I got from 7 months ago and just go out and do the pressure/load testing again. |
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@ 04:39 pm (GMT) |
Nathan FosterRe: Load Data : 7mm RM 162gr SSTHi Danny, 68 grains and 3030fps sounds about right to me. It is within the same 68-69.5 grain test range where I would expect things to be. I cannot see any problem with what you are doing. My concern with heavy brass was that you may hit excessive pressure slightly early but this would still see you above book max to reach this pressure. Sorry, I should have clarified this.Carry on... The worst combo would be heavy walled brass and short throat. Situations like this can really catch a powder manufacturer out. A no throat chamber is the worst, the smith forgetting that his tooling utilized a separate throating reamer. |
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@ 06:48 am (GMT) |
deerndingoRe: Load Data : 7mm RM 162gr SSTThanks Nathan. I'm being careful. The test range you talk of reinforces mine.Sometimes its good to just look over your neighbours shoulder and see he's cutting grass the same way you are. Again, thanks Nathan. |
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