7mm Mag Norma Brass, too soft?

[naja302]

Hey, first post here. Mostly I just come here to learn by reading other posts, but this is bugging me so I figured I ask for some advice.

I gave up on the 338 Lapua after not being able to get acceptable accuracy with 3 different guns...the last of which being outrageously expensive (problem must be me). So I figured I would try this 7mm mag thing that everyone seems to think is so good (despite my pre-conceived notion that its basically equivalent to a 30-06).

I have a sour taste from expensive guns that shoot 2MOA, so I bought a Remington 700 long range in 7mm mag for $750. I wanted fancy brass so I bought 100 pieces of Norma brass.

Facts:

• I have fired less than 200 rounds through the gun
• I am new to the 7mm Rem Mag
• I have fired 13 different 5 shot groups under MOA and 6 of those were roughly .5MOA. This is outstanding and I have never had this kind of repeatable accuracy with anything.
• I have shot mostly 168 bergers and they shot best at Zero clearance
• Velocity is very slow and when I get to 2900 fps extraction is very stiff and I had to use a cleaning rod to remove several rounds.
• I neck sized the brass and they would not chamber (without a fair amount of force) These rounds when chambered scraped the case immediately in front of the belt.
• 150 barnes TTSX shot great but same severe extaction trouble at 2850-2900 FPS (loaded with .050" clearance and I did not try any other depths)
• Remington Factory 150 cor-lokts shot fine and chronographed 3112 without ext trouble
• R/P brass is 10-15 grains heavier than the Norma brass
• Norma brass varies by about 2 grains in weight
• R/P brass varies by about 10 grains in weight
• My chronographs reads normal type velocities with the other guns I am shooting so I don't thing that it is significantly off.
• I was expecting 3000-3050 FPS with the 168g (maybe that's just not reasonable)

Brief synopsis of some of the loads I tried:

• 68g H1000 with Norma brass and Fed 215 GMM primers @ 2744 FPS (69 and 70 grains gave significant extraction trouble)
• 68g Retumbo with Norma brass and Fed 215 GMM Primer @ 2825 FPS (69 and 70 grains gave significant extraction trouble)
• 150g TTSX with 59g H4831SC, Norma Brass, Fed 215 GMM primers @ 2672FPS (60 grains and above gave extraction trouble)
• 168 VLD, R/P brass, Fed 210 GMM, 70g Retumbo @ 2970FPS without ext trouble but poor accuracy

I read some stuff on here and realized that I should not utilize mag primers so I loaded some more up with Fed 210 GMM primer and now utilizing once fired Norma brass was able to shoot the 68g load of Retumbo at 2825 with only ext trouble with about 1 out of 10 shots. I loaded this load up to go hunting and after my hunt I went to the 1000 yard range and verified drop at 500, 800 and 1000 yards. Drop matched what my G7 BR2 gave me exactly so that gives me some reassurance in the velocity being at least close to correct.

I am definitely seeing pressure signs, but I think the brass is just soft down in the belt region and its probably not actually a high pressure load or I would see faster velocities to go with the extreme pressure.

I loaded some in some once fired R/P brass and group size doubled, but velocity increased by 150fps without ext trouble.

I am a believer that pressure equals velocity. SO I am thus convinced that the norma brass is expanding excessively under normal pressures...Anyone agree?

If I didn't own a chronographs I would be really happy cause this thing is shooting very well, but there is a big difference in 2825 and 3025 FPS (at least in my mind).

Should I be happy with 2825 FPS?
Should I sort and prep R/P brass and hope to get good accuracy with that AND more velocity?

Thanks, and I hope the above makes some sense.

Danny

 

[jlostrander]

I have a similar issue with a gun I have. It is a lazzaroni chambering. So, I can only use lazz. brass. It will shoot new brass well, with no issues. However, once fired will not extract. Have to take them out with the rod. I believe the chamber on my gun is not perfect and thus this is the result. At least in your situation, you can try other brass. Do that and tell us what happens. Also, try some loaded ammo, I saw HSM loaded with the bergers at a reasonable price. You should try those and try reloading other brass. I also tried having my chamber polished, this did nothing.

 

[wbm]

I have fired 13 different 5 shot groups under MOA and 6 of those were roughly .5MOA. This is outstanding

It is indeed. Seems to me your problem may not be Norma brass but expectations. You have a rifle that is very accurate at certain velocity projectile combinations but you are not satisfied with the velocity so you up your powder charge rates to get more speed. When you do that you end up with serious extraction and accuracy problems. First of all you are putting the Bergers against the lands. This results in higher pressure spikes....sometimes very high pressure spikes. With high volumes of slow powder don't use non magnum primers....using non magnum primers in itself can sometimes cause pressure problems. Second you are assuming that you have a "normal" Remington barrel and chamber. You may not have that....you may have a tighter than average chamber and bore....nothing wrong with that it just means you have to adjust your loads and expectations of velocity accordingly.

Finally, a 168gr Berger VLD with a G7 BC=.313 moving at 2850fps (at sea level) is one flat shooting mutha and still has sufficient velocity and energy to drop a pachyderm at 800 yards! That gets it done for me.

The 7mm Remington Magnum is my favorite all around do it all cartridge. I have a Savage 110 with a 26" Criterion barrel that will shoot extremely well with 160gr Sierra Game Kings....the velocity is about 2900 fps and three shot groups commonly average less than .30"....why would I want more velocity at the expense of accuracy? To me, in long range shooting speed is important accuracy is everything. Personally I think you have a pretty outstanding rifle.

 

[RobG5589]

Norma brass is reportedly very good. Are you seeing ejector swipes or excessively flattened primers? The brass will only expand as far as the chamber will allow. I would look at the chamber for finish. If it is rough the brass can "stick" after firing. Rem chambers can be pretty sloppily cut at times. I shoot with a guy that had similar issues and after polishing the chamber all was good.

I have shot some pretty hot 7RM loads (3000+ with a 180 smk) from a custom chamber with cheap Rem bulk brass without the issues you are describing. I have even blown primers yet the brass still extracts.

Like wbm stated, the load you came up with is pretty **** good. Guns/chambers vary, what works in one will not in another. I would rock the 168 at 2850 and not look back.

Good luck, it's gotta be frustrating.

ETA: So I was bored and jumped on JBM. Here is 2850 vs 3050. Zero'd at 300 and going out out 700 yds.


inches of drop -73.3 moa of drop -10.0 inches of drift 25.8 moa of drift 3.5
inches of drop -85.4 moa of drop -11.7 inches of drift 28.7 moa of drift 3.9

Personally, I would take the good accuracy and spin the dial another rev.

 

[dsculley]

Try loading the 168 Bergers with a .070" jump. That seems to be the sweet spot for those. That is from my experience and from several other good shooters.

FWIW,

Dennis

 

[g0rd0]

Since the mid 70's I have experience with 338wm, 300wm, 3006,308, 3030, 7mm08, 7mmrm, and 243. My absolute fav is 7mmrm, hands down. There is no north American big game that cannot be easly harvested with it. Not to mention that you can get ammunition any where.
I load from 139grn hornady sp's up to 175grn sp's. My rifle likes them all.
My fav hunting load is 150grn ETIP FL sized 3.250" OAL CCI mag primer 67.0grn IMR7828 Fed brass (3010 fps) chronoed
I have also tryed win, rp and hornady but my rifle prefers the federal, go figure. The rp brass wants to stick in my chamber (witch is my only complaint with rp), the win was plated and I am not a fan of the plated stuff so I gave it away and I had trouble seating bullets with the hornady (I figured it to be too soft).
All of my brass I get from factory ammo. I have never bought unloaded brass.
If you are not happy with any brand of brass sell it or give it away and try another. Price has never guaranteed quality

 

[MudRunner2005]

For every caliber I reload for, I have had the best results with Nosler, Lapua, Winchester, and Hornady brass. I primarily use Nosler since it is pre-prepped and weight-sorted before packaging. Same goes for Lapua. Always had awesome luck with those 2.

7mm RemMag is my favorite deer hunting caliber. I use 65.5gr of 7828 SSC in Nosler brass behind a Berger 168 VLD. I get 3,115 fps MV from my 26" barreled primary deer rifle.

 

[shawnb]

for my first custom 7mm i used norma brass. the loads were not hot and i ran the 180vld at 2950-2975 and the 168vld at 3025ish. the brass lasted 4 loads before the primer pockets were gone.

i switched to winchester brass and annealed them after fireforming and they are going on 8 reloads with no problems or signs of giving up at full house loads.

$250/100 norma vs $95/100 winchester.... not a hard choice for me.

 

[deadidarren]

this is just my opinion , i don't think it is a soft brass prob as much as it is a not enough brass in the web .

as you will see in the pic there is a lot of brass missing in the web area (norma on the left .
ever noticed the bit just in front of the belt that dosent expand well not in the norma i believe this is what is causing the case to get stuck.

with the run of the mill brass (rem win fed) i can load up to 73g of H1000 with a 168 buger VLDH before i get bolt lift problems not with norma best i can get is 67g and 2700fps , i may as well get a 708.

and with the 180g vld in good brass i load 69g of H1000 for 2960fps not in the norma 65g and very sticky bolt lift .

so no more norma for me .

 

[shawnb]

I agree with what you are saying. And that 69gr with a 180 is magic in any rifle.

 

[naja302]

Thanks for the replies. I will, of course, continue to tinker with it and see what I get. I do think that 200 FPS is significant. I feel like I am losing almost 200 yards of effective range.

I am going deer hunting next weekend and I will take this cause, well, Coues deer are tiny and I think this probably wont bounce off.


Danny

 

[wbm]

I do think that 200 FPS is significant.

Perhaps a bit less so than high pressure and extraction problems.....but to each his own.

 

[chad44]

It is indeed. Seems to me your problem may not be Norma brass but expectations. You have a rifle that is very accurate at certain velocity projectile combinations but you are not satisfied with the velocity so you up your powder charge rates to get more speed. When you do that you end up with serious extraction and accuracy problems. First of all you are putting the Bergers against the lands. This results in higher pressure spikes....sometimes very high pressure spikes. With high volumes of slow powder don't use non magnum primers....using non magnum primers in itself can sometimes cause pressure problems. Second you are assuming that you have a "normal" Remington barrel and chamber. You may not have that....you may have a tighter than average chamber and bore....nothing wrong with that it just means you have to adjust your loads and expectations of velocity accordingly.

Finally, a 168gr Berger VLD with a G7 BC=.313 moving at 2850fps (at sea level) is one flat shooting mutha and still has sufficient velocity and energy to drop a pachyderm at 800 yards! That gets it done for me.

The 7mm Remington Magnum is my favorite all around do it all cartridge. I have a Savage 110 with a 26" Criterion barrel that will shoot extremely well with 160gr Sierra Game Kings....the velocity is about 2900 fps and three shot groups commonly average less than .30"....why would I want more velocity at the expense of accuracy? To me, in long range shooting speed is important accuracy is everything. Personally I think you have a pretty outstanding rifle.

I agree. These are good numbers and they won't get too much better imho. I shoot a 26 inch barreled custom rifle and I'm using 29.3 gr H1000 pushing 168 gr bergers at 2916 FPS. I didn't show signs of pressure til about 74 grs if I remember right but accuracy dropped off. A lot of guys report 3k + FPS for a 7RM and that's great but without accuracy it does no good. I'd rather be accurate then fast any day.

 

[wbm]

Think you have a typo....29.3gr H1000?