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7mm Rem Mag help

MTGunner

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Dec 19, 2010
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436
Location
NW Montana
Ya’ know, I go to the range in the morning when, hopefully, the wind is down. Temperature is cool and I haven’t had a cup of coffee. I load 140BT, 210 Fed. primers, 63.5 grains of IMR4350. COAL=3.300+/- .002 off the bench with my Sako A7 7MM Remington Magnum. I have a heavy front shooting rest with a BR attachment and rear shooting big ear bag for my rifle to assure consistent straight rear movement of this rifle. My loads are each measured, guess I am a bit anal about such. But, on any given morning my groups will vary from 1.00 to .75 average. I fire a fouled bbl. Each firing is from a cold bore. Having said this I may only fire 3-4 three shot groups in 2 hours.
I make it a point to do everything the same, if possible. But, none the less the groups vary in size. This is not the max load from Nosler. The manual test bbl. is 24” whereas my bbl. is 26”. So, there is a difference of test equipment, shooting facility and weather from Nosler range and my local range. But, if my Sako A7 will shoot 1” to sub 1” groups from a hunting rifle I am fairly pleased. Let’s face it, this is not a BR rifle. I am not a BR shooter. I calculate my loads for drop and windage at 50 degrees with no wind. Difficult to get my range with no wind. But, one has to realize if we do the best as we can reloading and shooting conditions that MOA is good for a hunting rifle. I make a range chart out to 500 yards with the drop and FPS. This helps me shooting from laying down and setting positions like in the field. Let’s face it, there are no shooting bench’s in the mountains and prairies. Set your rifle up for the most accurate load and practice, practice and practice more from actual hunting conditions. Get to know your equipment thoroughly. Good optics help immensely.
Hope this will help. Have been hunting and shooting for better than 45 yrs. Small things have helped for consistent shooting. The pics below are but a small amount of the 30+ mounts that are in my trophy room. I am but a mediocre shooter. I like to think I am a good hunter. I like to get as close as possible to make an ethical kill shot to assure the animal is dispatched cleanly. My ethical opinion. Good Luck! MTG
 

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220yotekiller

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Oct 15, 2017
Messages
420
so l went out and shot my load through a chronograph today, the results were less than steller. it was running an average of 2560 fps. l might try switching bullets and seeing if l can get the speed up. with speeds like that l might as well buy a 7mm-08.
 

Addicting

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Joined
Jan 19, 2017
Messages
5,623
Location
SW Michigan
so l went out and shot my load through a chronograph today, the results were less than steller. it was running an average of 2560 fps. l might try switching bullets and seeing if l can get the speed up. with speeds like that l might as well buy a 7mm-08.
That’s why you start with a chronograph before any grouping or seating depth.
 

Addicting

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Jan 19, 2017
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5,623
Location
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My go to powder was RL26 with 150g Barnes TTSX. They were traveling at 3150fps out of a 26” barrel. The BT have less engraving pressure and may need a 160g bullet to compensate for the lesser engraving of a bonded bullet.
 

220yotekiller

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Joined
Oct 15, 2017
Messages
420
l have been looking at my load data resorces, in my hornady book the max data for h4831 with a 150 gr bullet is 61 grains, but the nosler websight starts at 61 grains and goes up to 65 grains for the max. when l go to a higher weight, will my current oal be any good at all or should l treat it like l have never seen this data before. sorry for the lack of capitaliztion and weird punctuation, my computer is throwing a fit.
 

Farmerj

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Joined
Dec 12, 2021
Messages
544
I’d suggest getting this version for the cartridge…

The more I get into reloading and researching loads, it’s a mud pit. I mean there are so data to filter through, compile and make sense of.

We don’t use the same controlled setup that many documented sources say, “this is what we used to make this load and this data..”

It’s using the senses in front of ourselves and telling if it’s showing signs of over pressure etc.

I’m guessing much of this isn’t new to you.

I wouldn’t hesitate to go up in weight if you have NO sign of pressures. Especially with conflicting sources of data one showing maxed charges and others showing those are starting charges.

I’ve found this manual to be a better compilation of data and easier to compare loads.

3B8C1FD4-345A-4D32-B868-2AB0C753C11A.jpeg
 

WVmike

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Sep 6, 2020
Messages
144
Location
West Virginia
I would not worry about the difference in the size of those groups much. Strange thing about shooting groups, you seldom shoot the same spread group twice in a row, Has something to do with most us shooters! The difference between 1.380 and .908 just isn't that much! That's about .472, bit less than a 1/2". What would determine for me the value of the load would be the overall size of a number of groups. Somedays we just don't shoot as well as we do other days! Years ago I had a 7mm Rem Mag that I'd completely re-bedded and it shot great, averaged 5/8" groups. That does not mean every group was 5/8" but take a number of them and average them out and that's what I got. One of my most accurate shooting loads in it was with a 115gr bullet, not much of a big game bullet but boy did it shoot well. The way I decided what bullet to settle on is it got into a run off with the 160gr Speer and 154gr Hornady Spire Point! Speer won out by about 1/8" groups which didn't really amount to squat! But those were early years in reloading and at that time it ment a lot to me. Kind of ho-hum today!

Something you'll notice when shooting groups, 3 shot groups should be the smallest and it's one dumb animal that allows you more shots than that. But take that three shot group and shoot two more shot's often the group will open in size. Go to ten shots and normally will open more. I believe a lot of that is the shooter and the rest is a barrel getting dirty and hot. I've tried letting a rifle I was shooting on a to warm day sit about five minutes then touch the barrel and it's still hot! No idea how much that much heat actually effect's the bullet but probably some. Also I've super cleaned barrels thinking they would have to be more accurate and over the years I decided that I over cleaned them, the world famous fouling shot always seems to open the group some. Your out hunting and get a shot, the first shot you take will be the fouling shot!

if you shoot a number of three shot groups at a time, seem's they grow then too. maybe the heat, maybe the dirty barrel but some, has to be blamed on the shooter getting beat up with recoil! Seem's to wreack havoc with trigger control! So, go shoot several three or five shot groups over several days and figure out what the average size come out to.
I agree with this. I am fairly new to reloading having just started this year but not new to shooting with being in the military and also hunting since my teen years and I'm 32 now. I have a 7mm Rem Mag Weatherby Vanguard with a 26 inch barrel and I just tested my first 2 3 shot groups the other day. I used 150gr Hornady GMX with 250 CCI primers, IMR 4350 and started the first 3 shot group at the starting suggested load at 57.5gr from my Nosler reloading book and the results were 2 shots 3 inches to the right about an inch apart and the 3 shot hitting center of the center dot. The 2nd load I used was 59.0gr with the same primers and bullets and my group was less than 3/4" at 100 yards. I don't believe for a second that the 1st loads were that bad, it was more me as a shooter and with the first 3 shot group being the first 3 shots I took after one shot to verify my zero. I also let my rifle cool down in between the 2 groups before shooting the second group and there was also a heck of thunderstorm moving in and lightning. With that group of the second test being so small, I'm going to run with that load and go from there.
 

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BenInMT

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Joined
Feb 14, 2021
Messages
384
Location
Western Montana
so l went out and shot my load through a chronograph today, the results were less than steller. it was running an average of 2560 fps. l might try switching bullets and seeing if l can get the speed up. with speeds like that l might as well buy a 7mm-08.
I usually start with a google search for threads all over the internet where people have hashed out the same powder and bullet combo I am looking at. Certainly I don’t just go on that but if a lot of those before me seem to agree on a certain combo I will work up to it. That speed is anemic and i wouldn’t accept it, there is probably a much higher accuracy node somewhere north of 3000 FPS.
 

Don Fischer

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Joined
Jun 27, 2017
Messages
2,237
My 7mm Rem Mag was an L61R Sako. Fooled with a number if different bullet's. Some shot very well but all shot pretty good. I found there was one powder the really shined, N-205; it's gone now! One of my most accurate loads in it was using a 140gr Sierra. Can't saay much for Sierra hunting bullet's in those days, little bombs! But wanted badly to get the 160gr Speer Hot Core to shoot well and just wasn't getting there. Finally got to thinking if that 160gr bullet was loaded no deeper than the 140gr it might work? I was young back then! Well was no way to do that. had room in the magazine but not the chamber. Finally loaded up a dummy round for that rifle with the 160gr bullet seated to the junction of the neck and shoulder and the bullet just off the lands. Gunsmith in Kalispell, Montana fixed it up for me, Joe Dezivi! Looked like a spear but, shot like, out of this world. Something I really liked about that Speer bullet was the hot core. I shot that bullet into bundled newspaper at 100yds and the bullet's retained 85% of their weight and the core and the jacket were tight! Did the sake with 154gr Hornady's and retained 85% but i could turn the core in the jacket. That hot core bullet was the origional bonded core bullet! I used them in that rifle till the rifle went away. Today I use the 140gr hot core in my 6.5x55 and 6.5x06. Speer was light years ahead of their time with that hot core bullet. I don't thinkthe get proper credit today in fact. Hard for a Hornady fan to say!

Forgot to add. The original160gr Hot Core load was 67.0 grs N 205 but after having the chabmed re-cut, max load in that rifle went to 69.0grs. With todays rifles i can not do that. every rifle I though about it with I found the magazine well to short to do it.
 
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Cornbread

Active member
Joined
Oct 13, 2021
Messages
166
I would not worry about the difference in the size of those groups much. Strange thing about shooting groups, you seldom shoot the same spread group twice in a row, Has something to do with most us shooters! The difference between 1.380 and .908 just isn't that much! That's about .472, bit less than a 1/2". What would determine for me the value of the load would be the overall size of a number of groups. Somedays we just don't shoot as well as we do other days! Years ago I had a 7mm Rem Mag that I'd completely re-bedded and it shot great, averaged 5/8" groups. That does not mean every group was 5/8" but take a number of them and average them out and that's what I got. One of my most accurate shooting loads in it was with a 115gr bullet, not much of a big game bullet but boy did it shoot well. The way I decided what bullet to settle on is it got into a run off with the 160gr Speer and 154gr Hornady Spire Point! Speer won out by about 1/8" groups which didn't really amount to squat! But those were early years in reloading and at that time it ment a lot to me. Kind of ho-hum today!

Something you'll notice when shooting groups, 3 shot groups should be the smallest and it's one dumb animal that allows you more shots than that. But take that three shot group and shoot two more shot's often the group will open in size. Go to ten shots and normally will open more. I believe a lot of that is the shooter and the rest is a barrel getting dirty and hot. I've tried letting a rifle I was shooting on a to warm day sit about five minutes then touch the barrel and it's still hot! No idea how much that much heat actually effect's the bullet but probably some. Also I've super cleaned barrels thinking they would have to be more accurate and over the years I decided that I over cleaned them, the world famous fouling shot always seems to open the group some. Your out hunting and get a shot, the first shot you take will be the fouling shot!

if you shoot a number of three shot groups at a time, seem's they grow then too. maybe the heat, maybe the dirty barrel but some, has to be blamed on the shooter getting beat up with recoil! Seem's to wreack havoc with trigger control! So, go shoot several three or five shot groups over several days and figure out what the average size come out to.
I always let my barrel cool down every 3 shots. I have even brought ice water to the range to cool it down quicker. IOnce I have sighted in my rifle for deer season, I never clean it until after the season. With these stainless steel barrels these days, and less corrosive powders, ya just don't need to clean it. It solely my opinion.
 

TXLonghorn

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Joined
Nov 29, 2020
Messages
265
I always let my barrel cool down every 3 shots. I have even brought ice water to the range to cool it down quicker. IOnce I have sighted in my rifle for deer season, I never clean it until after the season. With these stainless steel barrels these days, and less corrosive powders, ya just don't need to clean it. It solely my opinion.
I agree with you on that for sure. Mine shoots better with a fouled barrel I don’t want to mess that up by cleaning it. 😂
 

Don Fischer

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Joined
Jun 27, 2017
Messages
2,237
I always let my barrel cool down every 3 shots. I have even brought ice water to the range to cool it down quicker. IOnce I have sighted in my rifle for deer season, I never clean it until after the season. With these stainless steel barrels these days, and less corrosive powders, ya just don't need to clean it. It solely my opinion.
I don't generally clean during the season. I also found out a good cleaning ment having to shoot fouling shots all over again. Seems every rifle I have shoots fine with a little fouling in the barrel!
 

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