7mm-300 Norma Improved?

nodakhunter

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Thinking about a fast 7mm cartridge for a long range deer/elk gun. I've looked at this cartridge vs. the 28 Nosler and am seriously leaning the 7mm-300 route due to the availability of quality brass. Any ideas on where to find dies and/or a chamber reamer? Haven't had much luck finding any info with a simple Internet search.
 

Rhovee

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Rbros is doing one called the 7RBH. IMO, it’s way overkill. A 28 Nosler is plenty horse power for deer and elk. A 300 or 338 NMI would be better. Peterson and Lapua make brass.
 

Mram10us

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Call the reamer manufacturers and I bet someone has a reamer idea for ya. Keep us updated
 

traper

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l have a 7mm 300 Norma AI and 28 nosler if you would like to talk call 541 290 3949
 

LeddSlinger

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Thinking about a fast 7mm cartridge for a long range deer/elk gun. I've looked at this cartridge vs. the 28 Nosler and am seriously leaning the 7mm-300 route due to the availability of quality brass. Any ideas on where to find dies and/or a chamber reamer? Haven't had much luck finding any info with a simple Internet search.

JGS will help you to design and make a reamer for whatever you want.

Whidden Gunworks can make you a custom set of dies for whatever you dream up as well. Just send them a copy of the reamer drawing. But I wouldnt try to have dies made from a reamer print that came from anyone other than JGS. Other reamer manufacturers dont provide nearly as much detail in their reamer dimensional drawings. The detail of the JGS drawing helps to ensure your FL sizing die is made correctly.

Plus JGS makes the very best reamers on the market in my opinion.
 

Swamplord

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been there done that and moved on to the 338, a much better moustrap than anything in 7mm

you can call PT&G and order a reamer for the 7mm LRH anytime you want and Whidden has made reloading and hydro forming dies for it and can again

a local fella loves it immensley and is willing to put up the initial cost of having ready to load headstamped brass made for it by RCC, if that happens then I'll chamber my 7 tw Bartlein bbl and play with it some more, 3300 fps is about tops with the 195 gr Berger OTM, my rifle shoots one hole 3 shot groups at 3225 fps without pushing it hard
 

Short Case

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View attachment 156557 View attachment 156556 been there done that and moved on to the 338, a much better moustrap than anything in 7mm

you can call PT&G and order a reamer for the 7mm LRH anytime you want and Whidden has made reloading and hydro forming dies for it and can again

a local fella loves it immensley and is willing to put up the initial cost of having ready to load headstamped brass made for it by RCC, if that happens then I'll chamber my 7 tw Bartlein bbl and play with it some more, 3300 fps is about tops with the 195 gr Berger OTM, my rifle shoots one hole 3 shot groups at 3225 fps without pushing it hard
I have a 7-300 norma reamer and go gauge if you want one, I'm running my 7-300
3250 fps with the 195 berger, send me your phone number and I will tell everything I can about it

Don
 

highdrum

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300nm has same cap as 28 nosler, and same case length. Imp will get another 6-7 grains maybe more depending on angles. The main benefit is arresting case growth and brass flow that the norma is bad for. Personally I'd just get a 28 nosler and run a 28" barrel, it'll run within 50-75 fps od the 7-300nmi and components will be MUCH easier to find, load data/info is everywhere. Take this info from a guy running a 300 nmi, who also owns a 30 nosler!
 

LeddSlinger

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300nm has same cap as 28 nosler, and same case length. Imp will get another 6-7 grains maybe more depending on angles. The main benefit is arresting case growth and brass flow that the norma is bad for. Personally I'd just get a 28 nosler and run a 28" barrel, it'll run within 50-75 fps od the 7-300nmi and components will be MUCH easier to find, load data/info is everywhere. Take this info from a guy running a 300 nmi, who also owns a 30 nosler!

Sounds like you don't know how to maximize speed in the 300 NMI case if you think a 30 Nosler will run within 50 fps...

I have two 300 NMI's (110gr H2O capacity) and a 28 Nosler, although I havent worked with the 28 Nos yet as I just built it this summer. My father in law has a 30-28 Nosler and has loaded the 30 Nosler for customers. We know all about em.

If you truly have a 30 Nosler and a 300 NMI, you would know that the 300 Norma case is about .060" shorter than a 30 Nosler. A 28 Nosler is almost another .030" longer than the 30 Nosler.

Plus what if the OP already has an action with a Lapua bolt face he plans on using? The case rim on the Noslers obviously wont work in a Lapua action.
The guy hasnt posted once since his original post so who knows...just a thought
 

highdrum

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Sounds like you don't know how to maximize speed in the 300 NMI case if you think a 30 Nosler will run within 50 fps...

I have two 300 NMI's (110gr H2O capacity) and a 28 Nosler, although I havent worked with the 28 Nos yet as I just built it this summer. My father in law has a 30-28 Nosler and has loaded the 30 Nosler for customers. We know all about em.

If you truly have a 30 Nosler and a 300 NMI, you would know that the 300 Norma case is about .060" shorter than a 30 Nosler. A 28 Nosler is almost another .030" longer than the 30 Nosler.

Plus what if the OP already has an action with a Lapua bolt face he plans on using? The case rim on the Noslers obviously wont work in a Lapua action.
The guy hasnt posted once since his original post so who knows...just a thought
My piercision 300nmi will push bullets of equal weight 125-150 fps faster than the 30 nosler. ADG 28 NOS brass has 103gr capacity. Stepping down a caliber and going more overbore w/o increasing barrel length decreases the efficiency of your increased capacity, more than likely RL33, N570, H50BMG, maybe US869 will be best powders. The barrel life will be short as you'll be almost identical to 7mm rum charges, but it's your choice. 195 Bergers get explosive at extreme speeds, maybe he's banking on the new 190 a tip. Slowing your twist to 8.5 may be an idea since you'll be getting 3300 fps or so. Maybe he hasn't gotten a Rigby faced action yet and is just casting bets for input on his build? I'm just adding an opinion of practicality with the setup. My new 7mm will be a Sherman max, which only holds 78gr capacity, with charges around 70gr N570 pushes a 195 close to 3000 fps from a 26" barrel, 30% less powder for 10% less speed. My only reasoning for my post. I'm out of this conversation.
 

LeddSlinger

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Yeah I only run 215gr Bergers at 3140fps from my 300 NMI with a 26" barrel and 92gr of N570. Can swap to a faster powder and push them much faster, but 3140 fps is plenty fast and will be easier on my Proof carbon barrel.

In my 300 MNI target rifle (Sam chamber), I hit over 3200 fps with 230gr bullets, but the barrel on that rifle is 31". Never tested it much further. Actually just sold the target rifle so I'll only have one 300 NMI after this weekend.
 

nodakhunter

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Sounds like you don't know how to maximize speed in the 300 NMI case if you think a 30 Nosler will run within 50 fps...

I have two 300 NMI's (110gr H2O capacity) and a 28 Nosler, although I havent worked with the 28 Nos yet as I just built it this summer. My father in law has a 30-28 Nosler and has loaded the 30 Nosler for customers. We know all about em.

If you truly have a 30 Nosler and a 300 NMI, you would know that the 300 Norma case is about .060" shorter than a 30 Nosler. A 28 Nosler is almost another .030" longer than the 30 Nosler.

Plus what if the OP already has an action with a Lapua bolt face he plans on using? The case rim on the Noslers obviously wont work in a Lapua action.
The guy hasnt posted once since his original post so who knows...just a thought
DrillDog, you are spot on. I should have included that in my original post. The action I'm planning to build on is a Deviant Tactical with the Rigby bolt face, hence my interest in the Norma case. Would a 26" barrel be sufficient to get good velocities out of this cartridge or would a 28"+ barrel be necessary to burn all that powder?
 

RH300UM

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Some words of advice. Like Swamlord says. Go for the 300 NMI. Or the 338 NMI. The 7 is way to finicky and touchy with a negative investment to rewards equation. Having worked on the cartridge for 10+ years and refusing to submit to the obvious we kept at it. Many reamer design changes (6) were made in efforts to find the “best” way to make it work like we dreamed. When Lapua brought out brass things improved somewhat but we had already been using 423 Dakota brass made by Lapua so we had already reached the limits of the designs we had in reamers.
Things became very apparent after hundreds of rounds and numerous barrels burned. Yea stubbornness played in a lot here.
Here is what we found. The 200 wildcats went away so that left the 195 Berger’s.
The 195 Berger’s will not stabilize at high speed. Once speeds go over 3250fps this bullet goes crazy. Groups open drastically. 8 twist and 8.4 twist both. 26 inch long. Keep them at or under 3250 and it’s a one hole tack driver. Copper fouling in the barrels (Proof Research) was horrible at the upper speeds. Other bullets were pushed over 3400 fps. The Hammer hunter in 177 grains was a winner in the lighter 180 class bullets but with its BC is a long range deterioration game. Past 1k really had problems with wind. That’s enough there for another thread somewhere. 180 hybrids started to vaporize out of the barrels at times at 3250 fps and above. 180 eldms are just to explosive at under 500 (tested in a 7saum at 3030 fps at the muzzle. 4 elk and 2 deer from 400 to 630 yards) with the velocity they could be pushed to in this case so we didn’t use them. Maybe the 190 Atips will perform better?.
Also when things got above the 3250fps range the rifle began to have drastic torque added into the recoil which added to accuracy issues.
These rifles are 10 pound rigs designed for hunting.
Powder selection is limited for this highly over bore hotrod. Retumbo,RL33 and N570 being the 3 most able to give these velocities with the heavies. Add RL26 for the 180 weight class. Tested 8133 and LRT with result that were not what we needed. 50bmg gives slower velocity and it runs out of case capacity before pressure is reached.
RL33 was to erratic with temp changes!
Then we found that N570 caused rapid throat erosion in the 7mm bores. One barrel was toast in 200 rounds. So now N570 is out on the 7 bore size for us now. Side note is in the 30 cal it performs without the throats being melted so far.
I believe the 28 Nosler is at the tops for case effectiveness and use for the 7mm bore.
When this barrel burns out On my 7 it’s going to have the 30 version put on it. 230 Berger at 3200fps is serious elk medicine.
Just my 2 cents from experience
 
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