Anyone own a 7mm 300 Win Mag?

Good round for 168 gn bergers... a little over 3200 fps. Used 78.5 gn of Retumbo, it was a full case.
 
Its a good round but its not the be all and end all. I wouldn't want to give that impression. The 7mm Rem Mags with 26" barrels usually give 2950fps or there abouts with 180 grain bullets. A 28" barrel will yield around 3000fps with H1000. Whether driving a 162gr bullet or 180gr bullet, the 7mm RM is very capable out to 1100 yards. Past 1100 yards, it gets difficult no matter what you use, the faster 7mm-300 gives the user an edge, but he or she still must learn to read environmental conditions and gain a feel for what is happening down range where wind meters can't take readings etc etc. However, that is what I would consider to be the advantage of the 7mm-300's, for shooting between the ranges of 1100 and 1300 yards. Of course, the 7mm-300 does suffer less wind drift at all ranges, a definite advantage.

It really depends on how far you want to push your ranges. One of the locals here recently shot a group a shade under 3" at 1km (1120 yards) with the Practical, but thats a combination of more than just a good cartridge design and includes a good action, a good barrel, sound reloading practices and good shooting technique.

You asked about the reamer. The Practical Rev B reamer is available from PTG and requires a throating reamer seperately. This might be a good way for you to go as you will want to match your COAL to work with your internal magazine length minus 40 thou. This will avoid any unnecessarily long bullet jump. I believe the correct max COAL (VLD touching lands) will be 91.2mm (sorry about the metric), seat loads at 90.2mm. This max COAL should give smooth feeding from your magazine, plus flexibility with other bullet designs such as the A-Max. You'll need to double and triple check all of this.
 
The 7mm 300 Win is proving to be a good practical design but I'm starting to think that the 7LRM or 7mm 375 Ruger might just be even more of a good thing, its only 2.580" compared to 2.620" so more mag room, has no belt, and seems to be getting as good if not a bit more velocity than the 7mm 300 Win.lightbulb
 
Yes, the 7mm-375 Ruger is a good wildcat but guys do need to be aware of a couple of things. To avoid finicky performance, its best to have some freebore with this design, approximately .250". The case capacity is just a little too much to do otherwise.

The case capacity of the 7mm-300 is slightly less and the powder column narrower. The design works well with minimal freebore, decreasing bullet yaw along with no pressure spikes or any other finnicky performance. The belt on the 7mm-300 can be used to aid fireforming and fireforming loads can in turn be used for hunting, such is the level of control. I have used FF loads out to 1050 yards in my rifle, no loss of accuracy or change in POI. There certainly are a lot of subtleties involved.
 
I'm sorry to inform you that your reasoning about throat length is very flawed I have tried short and long throats in medium and very large 7mms with good results any problem you may have had would be with your chamber or throat design or maybe metal build up in the shoulder neck area. The 7LRM like the 7mm 300 Win would fit easily into a long 700 action with medium throat length, the accuracy of both cases are very good in well built rifles, the 7LRM just ticks more boxes at this time than the 7mm 300 Win at the moment.
 
Last edited:
I have no problems with the shouldered case of the 300 WM. When the 375 Ruger case has won as many competitions as the 300 Win, only then will I consider the 375 Ruger case may be superior. Not to mention, the RWS and Lapua brass is worth quite a bit to me.

Jeff
 
found one place selling RWS brass, and it is like 750 per 1k, and only per 1k... I don't think Lapua sells 300wm brass anymore do they?

Gary
 
found one place selling RWS brass, and it is like 750 per 1k, and only per 1k... I don't think Lapua sells 300wm brass anymore do they?

Gary

No, Lapua discontinued it. But new bxes still appear for sale now and then on here and other sites. I usually get a box about once a year when I see it for sale before someone else does. So my son and I have what we need and then some. The RWS I also have and use regularly. It is tough stuff but has a smaller case capacity. This makes it necessary to back loads off about 3 gr from the WW and RP brass. But Velocity was still in the 3200 fps range with 180's in the 7-300 and no sign of pressure.

Jeff
 
I appreciate all the input from you guys . Im still looking around at some different reamers , brass ,dies.
Thinking I may try doing a 7 rem mag and a 7-300 so i can do some side by side testing , as it seems hard to find a good comparison of the two .
 
I think the comparison would be much more interesting if one barrel was chambered for 7 mm Weatherby and the other 7-300 Win.

The 7mm Weatherby has tight chamber specs -great brass and easy to get quality dies.
There is much good loading data at different levels .

The 7-300 is most used here with the heavy match bullets in medium weight hunting rifles .

There is more new data for the new Berger bullets and others for these in Bryan Litz's revised book.

http://www.appliedballisticsllc.com/index_files/Book.htm

Glenn
 
Last edited:
We have put out five 7mm Practicals (7mm-300) over the last year and generally, I work on client 7mm Rem mags on a month to month basis. The average velocity gain for the 7-300 over the 7mmRM is 125fps.

The 7mm Weatherby produces pretty much the same velocities as the 7mm-300 via the use of free bore. The Weatherby case is roughly the same dimensions as the Rem Mag case but has a quarter inch bullet jump to allow extra gas expansion in order to create higher velocities. If the 7mm rem Mag is given a quarter inch freebore/bullet jump, the velocities are the same. That said, there is one major difference, the Weatherby cartridge is designed with a very long case neck to aid bullet to bore alignment. This goes on from what I was saying in a previous post about the subtleties of cartridge design. Don Allen did the same with his Dakota cartridges, these also have a quarter inch bullet jump but in order to counter yaw during the free flight from the case to the rifling, the case necks are very long.

The 7mm RUM by contrast has a short neck and .400 thou jump, nearly half an inch. This works OK with 180 grain bullets but some rifles simply won't shoot 160-168 grain bullets as the projectiles enter the rifling off center after completing the free jump. If you drop a 162gr A-Max into the chamber of a 7mm RUM rifle, then put a case behind that and close the bolt, the bullet will rattle both forwards and backwards, as well as side to side. There is quite a bit of room in the RUM throat- all designed for safe gas expansion towards the goal of highest possible velocities.

If the throat of the Weatherby is shortened, it will duplicate the 7mm Rem Mag. If you shorten the throat of the RUM, it can be dangerous with some loads due to the lack of room for gas expansion. I have documented experimentation with this on our site. Another set of documented results regarding overbore pressure problems can be found in Australian Sporting Shooter. Editor Nick Harvey built a .25 WSM with minimal freebore, the rifle reached dangerous pressures with what should of being mild loads, had one sweet spot, then back into high pressures when loads were increased. These types of results are not one off's, they can be repeated. Safety first.

When I designed our Practical reamer, I wanted a minimum freebore cartridge to remove one set of variables. Advised bullet jump is 40 thou. The design allows users the choice of a variety of bullet weights and styles. All of the five current rifles produce .3MOA or better. It is certainly not the only way to go and freebore isn't what I would describe as being of major detriment. There are three very common cartridges which I have to work with regularly for clients which utilize long freebore in their deign, the .308 Win, the 6.5x55 (Carl Gustaf rifles) and the 7x57. All are of course capable of excellent accuracy. However, with magnum powered cartridges, at the very least, an understanding of how freebore might effect results can be useful in determining how best to design a cartridge (such as including a long case neck), how to utilize the cartridge, choice of twist rate and how to troubleshoot problems encountered.
 
@Broz,

I just noticed (im a bit slow) that you are running an IOR with the MP8 Dot reticle. I have a 3x18-42 "Flea" scope, 1st gen with that same Ret. I absolutely love mine, for me it made a world of difference in how well I could "dial in" precision wise. That **** scope and Ret has me spoiled against others!

Have a good one,
Gary
P.S. Sorry for OT post
 
@Broz,

I just noticed (im a bit slow) that you are running an IOR with the MP8 Dot reticle. I have a 3x18-42 "Flea" scope, 1st gen with that same Ret. I absolutely love mine, for me it made a world of difference in how well I could "dial in" precision wise. That **** scope and Ret has me spoiled against others!

Have a good one,
Gary
P.S. Sorry for OT post

I prefer Nightforce to IOR but for sure the MP-8 Dot reticle is a hands down winner. If NF ever came out with a similar reticle I would be sending all mine in for a change out.

Jeff
 
The first Japanese Weatherby MK. V that I had in 7 MM Weatherby was chambered so that the 160 Nosler was seated to the base of the neck had a .025 jump to the lands.

This rifle shot everthing well with the factory 160 shooting .3 for 5 at 100 yards off rest.
72.6 gr MRP and the run out was less than.001 on the factory loaded rounds.

Fourty fired Norma brass weighed + or - 1/2 grain-
the very best weight varation that I've ever seen.

Unfortunately I lent this one to a friend including the cleaning rods.
In only three days he had rust in the last inch from condensation.

The next 7mm Weatherby was traded rather quickly for a Ferris Pindell built Witicha 6 PPC .

I still have an early Ruger # 1 in 7mm Rem.

In the late sixtys I necked down a few Dominion .300 Win brass to 7mm in my 7mm Rem dies.
The end result from the heavy brass used was no difference in capacity compared to Winchester 7mm Rem fired cases I was using then.

The 7mm Pratical advantage I believe is that the chamber diamensions are consistent and proper for accuracy throated for the heavy target bullets fired.
Slightly slower powders than that normally used in 7mm Rem are not compressed too much leading to eratic velocity -pressure.

What exactly is your current chamber fired case filled to the top with water capacity in the 7mm Pratical ?



7mm Rem rifles vary a LOT in chambers ,cases etc.

And a .311 loaded neck fired in a .321 chamber is a bit much clearance but works o.k. with Forester BR dies.


Glenn
 
Last edited:
Warning! This thread is more than 4 years ago old.
It's likely that no further discussion is required, in which case we recommend starting a new thread. If however you feel your response is required you can still do so.
Top