Maximum load for 7mm Rem Mag 160 gr Nosler Accubond

270Buck

Well-Known Member
Hi,

I am looking for some advice.

I have just got my 7mm Rem Mag and working up a load for it. I am using 160 gr Nosler Accubond and Viht N-165 which is easy to get hold of in the UK, so that is my definite powder of choice, although I do have plenty of N-160 but it’s a bit fast for a 7mm RM.

I have the 7td edition Nosler reloading manual. It states the starting load should be 57.0 gr and the maximum load should be 61 gr. The 61 gr load was the most accurate being sub 0.5 MOA. I have seated the bullet 20 thou off the lands.

When I chronoed the load the average was a mere but very consistent 2633 fps. The manual says it should be more like 2900+ fps. Their test barrel was 24" whereas mine is 25.5", so in theory should have a higher velocity than the Nosler test.

I realise all the manuals seem to over state the velocity but surely not by 300+fps!!

Looking at other reloading info, the Vihtavouri manual says for a Speer Grand Slam 160gr bullet the start load for N-165 should be 59.1gr and the maximum is 68.1gr this should produce 2982fps. The maximum load is 7.1 gr higher than Nosler state for their similar bullet.

The Hornady manual states for N-165 starting load of 52.7gr and maximum of 62.3gr for a similar bullet offered by Hornady.

My question is, how safe would it be to ignore the Nosler manual and try the Viht suggestion? I am wanting to get as close to 3000fps as possible.

I know I can make some rounds at say 1 grain increments and watch for pressure signs as I go, but I wonder if anyone else may have also done the same. I know all rifles are different so what is safe in someone else’s 7mm Rem Mag may not be safe for mine.

I am using brand new unfired Norma brass and Federal Gold Medal Large Magnum primers.

When I have shot 90 rounds I will neck size some brass and compare the same load vs unfired brass.

Any other suggestions would be appreciated.

Cheers
 
Try another chrono? Regards JCS

Yes, it does sound fishy. 57.0 gr of N-160 will send a 160-gr out of my .280 Rem or 7x64 at 2,900 fps.

Shoot the rifle at 100, 200, and 300 yards, groups of 3, and compare the drops. That will indicate the muzzle velocity, by playing with a ballistics calculator until you find something close to those groups.
 
Try another chrono? Regards JCS

Unfortunately I do not have access to another chrono?

Yes, it does sound fishy. 57.0 gr of N-160 will send a 160-gr out of my .280 Rem or 7x64 at 2,900 fps.

Shoot the rifle at 100, 200, and 300 yards, groups of 3, and compare the drops. That will indicate the muzzle velocity, by playing with a ballistics calculator until you find something close to those groups.

I am using N-165 for this load, although I do have N-160 that I could try. The manual states the N-160 would give a slower velocity than N-165 anyway.

I tried the drop method yesterday for the 61 gr loads, it dropped 0.7 MRAD measured using the reticle of my S&B PM2 and also confirmed with a tape measure. The Nosler ballistics software said it would drop 0.7 MRAD at the velocity of 2633 fps.
 
I have not shot the Nosler 160-gr in my 7x64 or .280 Rem. I shoot the Sierra GK SPBT and HPBT and the Speer Grand Slam ( for an even tougher bullet than the SGK HPBT). Maybe try one of those, or a Hornady 162-gr, to see if there is a diameter difference.

Maybe you can borrow a few bullets.

And maybe borrow some RL-22, RL-19, Magpro, H-4831sc, or IMR-7828.

What primers are you using? Be sure they are magnum primers. Change those, too.
 
Last edited:
I have not shot the Nosler 160-gr in my 7x64 or .280 Rem. I shoot the Sierra GK SPBT and HPBT and the Speer Grand Slam ( for an even tougher bullet than the SGK HPBT). Maybe try one of those, or a Hornady 162-gr, to see if there is a diameter difference.

Maybe you can borrow a few bullets.

And maybe borrow some RL-22, RL-19, Magpro, H-4831sc, or IMR-7828.

What primers are you using? Be sure they are magnum primers. Change those, too.

I have a few other bullets to try, but I want a bonded bullet, something on the heavier side hence me using Accubonds. I am going to South Africa in 2 weeks time and I want a heavy hitting flat trajectory round.

I am using Federal Gold Medal Large Magnum primers.

The Reloader and Hodgdons powders are not so readily available as what they are on your side of the water.

When I took up reloading I made a vow to myself that I would only use European powders due to the ease of procurement Vs American powders.
 
The Speer Grand Slam is a tough bullet. So is the SGK HPBT, and the SPBT is softer. The Sierras have very high BC, but if you are not shooting at 300 or 400 yards, who needs it? The Sierra HP 160 is probably as tough as the Accubond, if not more so.

The Federal GM250s are giving great accuracy. But try a CCI 250 for kicks. And try a Barnes bullet.
 
270Buck,
How do your reloads compare in OAL to factory offerings & to the OAL values published in your manuals & online?
If you are loading them long, your pressure will be low & that will obviously result in low velocity.

According to the Vihtavuori data (& drawing a charge weight /velocity graph to interpolate), your 61grain powder load should give about 2730ft/sec, so you are definitely getting a slow result.

You are loading at 20 thou off the lands which is an arbitrary measurement relating to your rifle & not necessarily comparable to the published data. You may not make up all the desirable velocity difference by seating deeper, but it should help.

You have some bullets, powder & primers which should do the job, you have got a trajectory that matches the chrono results so you can believe your measured velocity.

Are you getting sooty cases after firing (an indication of poor ignition/low pressure)?

Assuming that you are not getting any high pressure signs, your best way forward is to trust the Vihtavuori data & work up your load. You may not get to the magical 3000ft/sec as you seem to have a "slow" barrel with the components / load mix you have tried, but you should get a lot closer.

Are you crimping the bullets? That can improve initial burn rate & pressure rise characteristics, particularly useful in big capacity cases.

You could try a different make or batch of primers, but that means starting again & you haven't got much time before you travel. You have a baseline so work up from that.

In my experience I have had more accurate velocity results by following powder makers' data than by using bullet makers' manuals, but that isn't with your calibre.

One final reminder - be aware of the different temperatures here compared to Africa & bear that in mind - don't take high pressure loads developed in chilly GB to scorching hot Africa or you could get excessive pressures.

Ian
 
I would take the manafacturers BC measurement with a pinch of salt. They can be way off which will make your velocity estimate from trajectory innacurate.
 
not the same but I found a significant difference between data and MV's in the 300WM

How close to book data are your Muzzle velocities?


Products - Lapua

[TABLE="class: reload_data, width: 674"]
[TR]
[TD]10,4[/TD]
[TD]160[/TD]
[TD]Naturalis[/TD]
[TD]Lapua[/TD]
[TD]81,8[/TD]
[TD]3.220[/TD]
[TD]N160[/TD]
[TD]3,15[/TD]
[TD]48.6[/TD]
[TD]753[/TD]
[TD]2470[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]3,76[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]58.0[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]859[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]2818[/TD]
[/TR]
[TR]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD]N165[/TD]
[TD]3,65[/TD]
[TD]56.3[/TD]
[TD]786[/TD]
[TD]2579[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]4,08[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]63.0[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]868[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]2848[/TD]
[/TR]
[TR]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD]N560[/TD]
[TD]3,67[/TD]
[TD]56.6[/TD]
[TD]843[/TD]
[TD]2766[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]4,03[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]62.2[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]943[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]3094[/TD]
[/TR]
[TR]
[TD]10,4[/TD]
[TD]160[/TD]
[TD]Grand Slam[/TD]
[TD]Speer[/TD]
[TD]82,0[/TD]
[TD]3.228[/TD]
[TD]N160[/TD]
[TD]3,31[/TD]
[TD]51.1[/TD]
[TD]784[/TD]
[TD]2572[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]3,99[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]61.6[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]880[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]2887[/TD]
[/TR]
[TR]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD]N165[/TD]
[TD]3,83[/TD]
[TD]59.1[/TD]
[TD]812[/TD]
[TD]2664[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]4,41[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]68.1[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]909[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]2982[/TD]
[/TR]
[TR]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD]N560[/TD]
[TD]3,91[/TD]
[TD]60.3[/TD]
[TD]823[/TD]
[TD]2700[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]4,45[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]68.7[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]925[/TD]
[TD="class: reload_grey, bgcolor: #DCDEDD"]3035[/TD]
[/TR]
[/TABLE]


your results don't look to be a million miles away from Lapua data though

56gr 2579fps
63gr 2848fps

7gr increase 270fps increase
roughly assuming 40fps per grain within that range
a 61gr load would be 2779fps
100fps off your results

 
I agree with Yorric. If you want to duplicate factory loads, or published load data, load like they did. Fl resize, seat to factory spec OAL (or recommended) and crimp. It it always the place to start.~Muir
 
The naturalis is a monometal projectile. Work from the speer data unless you are shooting barnes solid copper projectiles. There is more variation in 7 mm rem mag data accross books and components that any other caliber I think. You have to start low and work up with a chrono in most cases. you will nealy always be outside book data when you get 3000 or 3100 fps with a 160. However you can do it and get a safe load without pressure symptoms. .
 
Right, well I ended up going with the viht data and went over the Nosler maximum load.

I got an average of 2850fps when I went up to 66.3 grains. Interestingly enough 66.6 grains had pretty much the same average fps as 66.3 grains did.

I am now in a position where I have used 80 of the 100 pieces of brand new Norma brass. I have neck sized and cut to my desired length.

I have measured my case expansion, new VS once fired brass. On average the cases have expanded by 3.5%.

I know that every rifle is different, but any idea what the likelihood is that my load will not lose, first and foremost accuracy and secondly velocity.

I will more than likely make 3 rounds using 66.3gr with new brass and the same charge with once fired and see what difference it makes on accuracy and velocity.

I will also try a load working up to a 3.5% increase as I now have 3.5% more case capacity. This will mean my load could be 68.6 grains. Although the viht data says the maximum is 68.1 grains.

The new brass case capacity is 5.456 ml.

The once fired case capacity 5.647 ml.

Barrel length is 25.5"

I am leaving for South Africa for a PG hunt on Tuesday so I have limited time available for another serious batch of load testing!!

Any help/advice would be appreciated.

Cheers
 
Last edited:
if my new to once fired loads in 300WM were anything to go by the POI was identical at 100m
You will lose more accuracy through buck fever heartbeat than the difference between once fired neck sized and brand new FL sized
 
Hi,

I am looking for some advice.

I have just got my 7mm Rem Mag and working up a load for it. I am using 160 gr Nosler Accubond and Viht N-165 which is easy to get hold of in the UK, so that is my definite powder of choice, although I do have plenty of N-160 but it’s a bit fast for a 7mm RM.

I have the 7td edition Nosler reloading manual. It states the starting load should be 57.0 gr and the maximum load should be 61 gr. The 61 gr load was the most accurate being sub 0.5 MOA. I have seated the bullet 20 thou off the lands.

When I chronoed the load the average was a mere but very consistent 2633 fps. The manual says it should be more like 2900+ fps. Their test barrel was 24" whereas mine is 25.5", so in theory should have a higher velocity than the Nosler test.

I realise all the manuals seem to over state the velocity but surely not by 300+fps!!

Looking at other reloading info, the Vihtavouri manual says for a Speer Grand Slam 160gr bullet the start load for N-165 should be 59.1gr and the maximum is 68.1gr this should produce 2982fps. The maximum load is 7.1 gr higher than Nosler state for their similar bullet.

The Hornady manual states for N-165 starting load of 52.7gr and maximum of 62.3gr for a similar bullet offered by Hornady.

My question is, how safe would it be to ignore the Nosler manual and try the Viht suggestion? I am wanting to get as close to 3000fps as possible.

I know I can make some rounds at say 1 grain increments and watch for pressure signs as I go, but I wonder if anyone else may have also done the same. I know all rifles are different so what is safe in someone else’s 7mm Rem Mag may not be safe for mine.

I am using brand new unfired Norma brass and Federal Gold Medal Large Magnum primers.

When I have shot 90 rounds I will neck size some brass and compare the same load vs unfired brass.

Any other suggestions would be appreciated.

Cheers

Have just seen your post. Have sent you a PM.

The trouble is two-fold. The Nosler reloading manual is a little timid, and Norma brass is thinner. It takes an extra 2 grains or so in Norma cases to get comparable velocities to those delivered in Sako and Remington cases in the 7mm RM.
 
Have just seen your post. Have sent you a PM.

The trouble is two-fold. The Nosler reloading manual is a little timid, and Norma brass is thinner. It takes an extra 2 grains or so in Norma cases to get comparable velocities to those delivered in Sako and Remington cases in the 7mm RM.

Brilliant, thanks for your help.

Eagerly awaiting your PM.

I am off out to do some more load testing later. I have gone and made some more rounds last night. Batches of 3

66.3
66.6
66.9
67.2
67.5
67.8
68.1

The Viht data says I can go to 68.1gr, but I will be carefully looking for pressure signs as I go.
 
Brilliant, thanks for your help.

Eagerly awaiting your PM.

I am off out to do some more load testing later. I have gone and made some more rounds last night. Batches of 3

66.3
66.6
66.9
67.2
67.5
67.8
68.1

The Viht data says I can go to 68.1gr, but I will be carefully looking for pressure signs as I go.

Shooting your ladder and you start to see very rapidly rising velocity gains per small increase in powder charge you could be approaching overpressure-land. You might not even be able to see or feel pressure signs.

At that point it's probably wise to back off. Not because it's necessarily dangerous, but because the loads at that point and forward won't have the repeatable (regardless of temperature etc) accuracy you are looking for.
 
Finally I have a load that meets all my requirements.

66.3gr - 2863fps
66.6gr - 2923fps
66.9gr - 2940fps
67.2gr - 2951fps

The 67.2gr load started showing pressure signs. There was a circular mark from the extractor plunger. Plus there was only 11fps increase from the 66.9gr load.

Given there is negligible difference between velocity of the 66.9gr and 66.6gr, I made my decision based on accuracy. The 66.6gr load was just over a 1/2" group. More than accurate enough for my PG hunt next week.

I went home and promptly pulled the 9 remaining rounds.

I dare say if I had more time before I went to SA and played with the seating depth, I could tighten the group a bit more. The bullets are seated 20 thou off the lands, when I get home I will try 10 and 15 thou off the lands to see if that reduces my group size, although a 1/2" group is plenty good enough for hunting.
 
Do not forget that SA is a lot hotter than the UK and the heat may well increase the pressure on
Your reloads and affect there reliability .
Bob
 
Do not forget that SA is a lot hotter than the UK and the heat may well increase the pressure on
Your reloads and affect there reliability .
Bob

I was going to chip in that you're possibly heading into Academia here.

England in March ain't South Africa in March. Aside from temperature the altitude alone can make a big difference to starting pressures.
Not sure where you're going but the majority of SA is above 1000m which can do funny stuff.

Check zero and enjoy... :)
 
Back
Top