7-300 Norma Mag Improved. IT’S ALIVE!!

[Phil Rizzo]

Bore scope bore scope bore scope!

It may not be quite cool enough yet…

 

[Huntnful]

Hahaha I didn't feel like cleaning it in order to bore scope it honestly. But I'm not exaggerating. It took me probably 10 minutes to clean up my stuff, and 15 minutes to drive home. I could still barely hold onto the chamber area of the barrel when I got home hahahaha but brass came out perfect!

 

[E4aker]

So I'm not sure about the jacket failures specific with 4 groove barrels, but I'd imagine this is worst case scenario

I think the 9 twist is helping in this regard. Also brux groove geometry is more angled on the sides of the groove compared to other brands….this might be contributing to it also

I know that when I've had bullet blowups it's been in extreme rpm situations and typically happened past 100yds.

 

[RH300UM]

I think the 9 twist is helping in this regard. Also brux groove geometry is more angled on the sides of the groove compared to other brands….this might be contributing to it also

I know that when I've had bullet blowups it's been in extreme rpm situations and typically happened past 100yds.

I've had 2 brux barrels on my 7-300nmi's both would destroy 180 vlds. I had to use 180 Hybrids to avoid the problems. I've had no issues with the Proof barrels
My sons rifle uses the 180 vlds now with the proof barrel
I use the 195's in my rifle
Also a proof

 

[E4aker]

I've had 2 brux barrels on my 7-300nmi's both would destroy 180 vlds. I had to use 180 Hybrids to avoid the problems. I've had no issues with the Proof barrels
My sons rifle uses the 180 vlds now with the proof barrel
I use the 195's in my rifle
Also a proof

Proofs current 6.5 and up barrels are 5 groove.

 

[nwmnbowhunter]

I would like to see a bartlein 400 mod bb barrel comparison. Seems like the perfect round to test one in.

 

[Huntnful]

I think the 9 twist is helping in this regard. Also brux groove geometry is more angled on the sides of the groove compared to other brands….this might be contributing to it also

I know that when I've had bullet blowups it's been in extreme rpm situations and typically happened past 100yds.

Good info for sure! The 180 ELDM's were my goal from the get go, so I may snag another 1-9 Brux and just take it easy on it. That thing sure did shoot well.

 

[Huntnful]

I've had 2 brux barrels on my 7-300nmi's both would destroy 180 vlds. I had to use 180 Hybrids to avoid the problems. I've had no issues with the Proof barrels
My sons rifle uses the 180 vlds now with the proof barrel
I use the 195's in my rifle
Also a proof

Good info! Thank you

 

[RichCoyle]

Still obviously learning this cartridge and what charge weight for what bullet weights. So this evenings test wasn't ideal.

I was over pressure on the 190 LRHT's and H1000 in my once fired brass. Which I honestly thought I had enough cushion not to be. I was wrong.

85gr. yielded a bolt click and 3200fps right of the bat

I had 5 loaded at 86gr. for the little accuracy test. I still decided to shoot all 5 because that's what I was there for and it didn't feel that dangerous. Shot just under a 1 MOA 5 shot group at 400 yards. Decent bolt lift for sure, so not ideal conditions for accuracy being that far into pressure. But I did find out that H1000 is really consistent, even in this under filled case, and into pressure.

This is 5 shots at 86gr. H1000 and 190 LRHT's
View attachment 547714

I believe I would have to drop down to 84gr. or possibly even 83gr. to get out of pressure with the 190's. So realistic velocity probably around 3100-3140fps with H1000.


Then I shot the 160 Copper Rose with Retumbo. They shot just over 1 MOA at 400 yards for 5 shots. Also not ideal, since they were loaded in my old 300 NMI that I just necked down for testing purposes.

87gr. 3436fps
88gr. 3460fps
89gr. 3470fps bolt click
90gr. 3523fps heavy bolt lift

5 shots at 87gr. Retumbo
View attachment 547722


Basically we're all just learning this cartridge together lol. Everything is new to me also. So I'm just trying to test and document data for future possible interests in the cartridge.

What do you think it would do with 130 grain class bullets? I'm thinking of doing one and using 132 grain Hammer Hunter tipped bullets.

 

[RH300UM]

What do you think it would do with 130 grain class bullets? I'm thinking of doing one and using 132 grain Hammer Hunter tipped bullets.

I'm guessing it would be over 3700fps

 

[Huntnful]

What do you think it would do with 130 grain class bullets? I'm thinking of doing one and using 132 grain Hammer Hunter tipped bullets.

Probably an extra 100fps for every 15gr. less of bullet. I can't imagine them going any slower than 3600. Probably much faster though.

 

[RichCoyle]

Thanks, guys.

 

[tacomHQ]

On that note, if it does die early how about a 7-378 or a 7-33 xc next?

Yep- 7-33xc. Dies and reamers are on order.

 

[Calvin45]

Yep- 7-33xc. Dies and reamers are on order.

Wait are you being for real here? I was being a facetious troll!!!! . But good lord man….you must keep us informed!!!!

What barrel length you gonna run? 50 inches? .

Did you notify NASA about this rocket?