7mm remmag powder with 165-180g bullets?

[MudRunner2005]

Just tried again, my best groups with 180 ELDM yesterday sucked today.
I tried 180 hybrids 71.4 Retumbo .015 off of the lands which was my best yesterday bad groups today.
180 hunting VLD's. 70.2 retumbo touching the lands 5 holes touching. So at least I have some hope, maybe this rifle just likes the bullets touching. I didn't chrono today left the magnetospeed off to see if maybe it was messing with my groups. Keep the advice coming I'm sure I'll get it figured out just frustrating right now. Thanks

1:9 Krieger 24". FTE brake not sure what the contour is.

Retumbo never worked for me in any cartridge. It was hit-or-miss. Worked for my buddy in his .300WM, but couldn't get it to do anything consistent in my 7mmRM or 7mm STW. So I stopped wasting bullets and primers.

I would highly recommend 7977 if your shooting 168 or heavier. During a hot (+95º) and humid (nearly tropical) Alabama summer day last year, I was getting 7 SD, and only 14 FPS ES in my .300 Ackley with 210's.

 

[millertime118]

OCW went from 70gr to 72.2 in .02 grain increments all .015 off the lands. 180 ELDM
70.4-70.8 gave me about my best group around 2815-2850. I was hoping I would get it over 2900 it just wouldn't get there. This is all nosler virgin brass CCI LRM primers.

 

[WWP2012]

OCW went from 70gr to 72.2 in .02 grain increments all .015 off the lands. 180 ELDM
70.4-70.8 gave me about my best group around 2815-2850. I was hoping I would get it over 2900 it just wouldn't get there. This is all nosler virgin brass CCI LRM primers.

It's not about the group size as it is about the velocity. Group size is changed by seating depth. What were the velocity for each group?

 

[L.Sherm]

I tried Retumbo in a Rbros. 7 mag of my nephews I could never get rid of a flier, speed was there but not accuracy. H1000 and 180 bergers is awesome.
I've tried Retumbo now in 4 or 5 rifles now and never have been satisfied.

 

[Capt RB]

Optimum Charge Weight revolves around barrel harmonics. The rifle will shoot different weights when in the ocw zone to the same velocity. Once you have that rough you would drop down to .1 or .2 from the bottom to the top of that node. Once you can identify the exact middle of that it would be seating if it's still not shooting well enough (doubtful). As far as velocity your getting. I know it's the internet and all but 2850 with a 24" 7mag is screaming. Especially with a factory tube. If you want velocity in that tube you can try slugging the barrel and lapping a taper in it but don't expect to shoot what most guys are getting with a custom 26" tube.
Tightening up your groups might just be a seating issue or a change of primers. I try to use 210/215's for loads. CCI's have a harder cup than Feds so for high pressure rounds cci's get the nod. I can get better es with Remingtons almost always but they run small so I might get 2 or 3 firings out of a case and either trash them or switch to feds or cci's which are .0005-.001 larger. and need to be tuned again.

 

[cape cove]

Don't have a 7mm Rem, but in my 7mm Weatherby mag Norma MRP works great with bullets ranging from 145 gr to 175. Give me top velocity with great accuracy.

 

[millertime118]

Retumbo 180 ELD-M .015 jump
70 2789, 2763, 2817 avg 2789 SD 27
70.2 2831, 2834, 2799 avg 2821 SD 19.4
70.4 2817, 2807; 2823 avg 2815 SD 8.1
70.6 2850, 2827, 2839 avg 2838 SD 11.5
70.8 2828, 2830, 2829 avg 2829 SD 1.0
71 2844, 2861, 2860 avg 2856 SD 11.5
71.2 2890, 2856; 2861 avg 2869 SD 18.3
71.4 2838, 2857, 2877 avg 2857 SD 19.4
71.6 2942, 2878, 2921 avg 2921 SD 37.2

 

[SabreCross]

I use h1000 with berger vld hunting... great powder.

 

[WWP2012]

Retumbo 180 ELD-M .015 jump
70 2789, 2763, 2817 avg 2789 SD 27
70.2 2831, 2834, 2799 avg 2821 SD 19.4
70.4 2817, 2807; 2823 avg 2815 SD 8.1
70.6 2850, 2827, 2839 avg 2838 SD 11.5
70.8 2828, 2830, 2829 avg 2829 SD 1.0
71 2844, 2861, 2860 avg 2856 SD 11.5
71.2 2890, 2856; 2861 avg 2869 SD 18.3
71.4 2838, 2857, 2877 avg 2857 SD 19.4
71.6 2942, 2878, 2921 avg 2921 SD 37.2

70.6- 70.8 is good but that one 2850 could of been a flyer. You will pick up some speed trying a different powder, H1000 or RL26. There is something going on and your extreme spread is not consistent across enough of those groups to be useable at longer ranges. The other powders may give you a more forgiving node with a few extra FPS with less powder per shot.

 

[millertime118]

No RL26 available I now have H1000, 7828SSC, RL23.

 

[Prieto9000]

I tried Retumbo in a Rbros. 7 mag of my nephews I could never get rid of a flier, speed was there but not accuracy. H1000 and 180 bergers is awesome.
I've tried Retumbo now in 4 or 5 rifles now and never have been satisfied.

Retumbo has worked very nice for me on several rifles. 7mm rem mag using 180 hybrids, 28 nosler pushing 180 ELDMs, 338 EDGE pushing 300gr hybrids and 285 a-max. I chose Retumbo over RL-33 on my 28 because even though RL-33 produces higher MV, retumbo is more consistent from hot to cold temps.

 

[WeiserBucks]

My 7 RM makes 2925 fps with less than 70 grains of H1000 and 180 Hybrids in a 23.5" barrel.

 

[millertime118]

I'll definitely give it a try thank you are you jumping your hybrids?

 

[millertime118]

Optimum Charge Weight revolves around barrel harmonics. The rifle will shoot different weights when in the ocw zone to the same velocity. Once you have that rough you would drop down to .1 or .2 from the bottom to the top of that node. Once you can identify the exact middle of that it would be seating if it's still not shooting well enough (doubtful). As far as velocity your getting. I know it's the internet and all but 2850 with a 24" 7mag is screaming. Especially with a factory tube. If you want velocity in that tube you can try slugging the barrel and lapping a taper in it but don't expect to shoot what most guys are getting with a custom 26" tube.
Tightening up your groups might just be a seating issue or a change of primers. I try to use 210/215's for loads. CCI's have a harder cup than Feds so for high pressure rounds cci's get the nod. I can get better es with Remingtons almost always but they run small so I might get 2 or 3 firings out of a case and either trash them or switch to feds or cci's which are .0005-.001 larger. and need to be tuned again.

It's a Krieger 5R 1:9