7mm Rem Mag 7977

wird06

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Nov 23, 2020
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North Carolina
Hello Everyone
I use to have an account on this amazing forum but I have since lost my password and changed email addresses due to the wonderful amount of spam!
The reason I am here this time is trying to gather some information. I have a7mm rem mag that I am changing the barrel from the factory barrel 1:9.25 twist to a Remage Criterion 26" 1:8 varmit barrel (super excited about this). The gun originated as a hunting rifle and over the years has progressed into a long range target rifle (1000-1400 yrds). My goal was to go from the 162 ELDX to a 180 ELDM in hopes the heavier bullet and better BC would help in the longer ranges. I was reloading 162 ELDX with 7977 and had great results on the factory barrel, I am getting my stuff together for the new barrel and i cannot find alot of information on the 7977 with 180gr. I was hoping to use this power as i still have several pounds left over and with the shortage its getting hard to find powder locally. What are your thoughts? Does anyone have any data on the 7977 with 180gr? I have heard the 7977 is very compariable to H1000. Should I just stick with the 162 in a 1:8 twist?
 

just_jon

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I would run the 180s if I only had a 1:8 twist. Attached is quickload data fromr 180 VLDH and IMR 7977. Use at your own risk.
 

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Jud96

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That quickload data is showing the cartridge with a 3.290” OAL with a 180gr Berger. You’ll most likely be closer to 3.400”+ when loading the 180 VLD closer to the lands. That extra room in the case will let you shoot a little more powder and will probably let you reach 2900fps.
 

wird06

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Nov 23, 2020
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North Carolina
Thank you.
Do you think going from the 162 to the 180 will have a noticeable difference at distances?
I will have some 162 left over by the time the barrel gets changed out and I thought about trying some but with powder and primers being hard to find I donno if its worth it.
 

Jud96

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There won’t be a huge difference. The heavier bullet will work a little better on game in my opinion, but ballistically they’ll be similar.
 

Capt RB

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Rl26 will get you close to 3000fps most likely closer to 3050. You will have a .2 mil/.68moa better wind drift at 650yds and 400#s of energy advantage @ 2900fps for both. In the testing that I have done the IMR powders 4955,7977 and 8133 in different applications all pressured out at 100-150fps slower than other powders with similar applications. 4955 in a creedmor would pressure out at 2690w/147's. Same rifle with Rl16,19 and 26 would run them over 2800fps in the same brass. 7977 in my brothers 7rem with the 162 is 150fps behind retumbo where it wants to shoot. I never saw 3000fps due to swipes and heavy bolt lift. 8133 in a 300rumI have done a work up on was 75fps behind at max and 130fps behind where it wanted to shoot. If you don't mind the lost of speed they are fine. I have 4#s of each at least with in case of emergency applications but I won't use it otherwise.
If a decoppering agent is a must for you. Tubb dust will do the same and you can add it to any powder.
 

wird06

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Nov 23, 2020
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North Carolina
Capt RB
Thank you for the information. The decoppering is a new subject for me, can you shed some light on this? The reason i used 7977 was when I started to reload the local gunsmith recommded it and it was easy to obtain, being i never had issues with it i didnt see a reason to change powders. This will be a brand new barrel and load workup, if you recommend RL26 I can see how hard it is to find the powder.
 

L.Sherm

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Speed dont mean nothing if it isn't accurate, 26 worked in one that I loaded for and H1000 worked in the other both with 180 Bergers. 26 was at 2950 and H1000 was at 2900 both in 26" barrels and neither would shoot Retumbo well.
 

Capt RB

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I have not had a rifle yet that wouldn't shoot well with Rl26 in 6.5 creedmoor 6.5/06ai, 270 win, 7mag, and 300prc. I had sd's in the low single digits and es of 6/10shots(6.5 creedmoor) es 3 270win, es of 9 7mag and I have not finished with the PRC however I have an es of 9 over 10 shots with the 195tmk using 4 different seating depths .003 apart yesterday. I still have not settled yet but am close to where It will remain.
The 6.5/06 was another low single digit es with very good accuracy. The new owner is running H1000 nowabout 100fps slowerwith the 156's. I ran 147's and 150 smk's at 3120 and 3110 respectively
 

Capt RB

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Here are 5 at 200yds yesterday. Rainy with gusts to 30 right to left. 195tmk 3085to3094. Was for 10 earlier. 30" barrel and about 1.8 grains off a swipe in hornady brass
 

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