Strongly considering a 7-300WM, but i have a few things to ask....

D

duncansuds

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As the title states, I am looking at building a 7-300wm or "practical" as it has also been called, I know that it is a slight margin over the 7RM, but that is what I am hoping for. I am planing on a 1-8.5 twisted barrel at 26-28" finished, cut for a 195 Berger EOL and aiming for a 3000fps velocity to get the desired performance out of that projectile. Now I am finding some mixed results and hoping some experience will chime in on the ups and downs of this cartridge choice.

Some of my main concerns are:

1. Barrel life.... Can I get to the 2500-3000rd mark without having to worry about my throat?

2. Is it actually easy to work with the brass like they say.. I have heard it's just swapping the neck bushing to 7mm and hit the press...

3. Primer pocket expansion should be good if I don't get greedy on velocity, I am hoping... Like 4+ loadings on each piece would be an ideal outcome with a thinner neck...

4. Needing custom dies to accommodate for properly seating a Berger correctly. ...


Any help or comment is appreciated, but I don't want a Rum, or a Dakota, STW is a little excessive too, or any other barrel killer, looking for a nice balance of velocity and reduced over-bore , thanks!
 
1. Barrel life.... Can I get to the 2500-3000rd mark without having to worry about my throat? You will likely see bore wear around 500rds... I doubt you will have much throat left after 1500rds. Good accuracy likely left around 800 to 1000rds.

2. Is it actually easy to work with the brass like they say.. I have heard it's just swapping the neck bushing to 7mm and hit the press... Necking down is easy

3. Primer pocket expansion should be good if I don't get greedy on velocity, I am hoping... Like 4+ loadings on each piece would be an ideal outcome with a thinner neck... depends on the manf brass and pressures you run.

4. Needing custom dies to accommodate for properly seating a Berger correctly. ... No.. A Forster seater should work fine.

3000fps is very ambitious at safe pressures. You will be hard pressed to find published load data with the 180gr that beats 3000fps at magnum pressures. The 195gr will be 100 to 200fps slower for the same pressure and bore length

If you want 3000fps with the 195gr, you are going into a very big case... and very short bore life.

No free lunch with this one...Sorry, I read WSM not 300WM case the first time.

7 STW might be about the min to touch what you want

Jerry
 
Ok. Most of that makes sense, except that I was reading that bore life is pretty good (way better then a 7RUM and even better then stw) but no one had a figure to back that up.
 
It would be much less work to just use the 7LRM from Gunworks. That is what I am chambering in. You can buy the brass already formed and headstamped from Grouse River. It will get you to 3150fps with Sammi spec pressures with the 180s. This should get you to 3000fps with 195s or pretty close.

There is no free lunch with barrel life. I am expecting 1200-1500 top accuracy levels from this cartridge. Overbore is overbore. But Gunworks built it with a very long neck to help with that. It has a little more case capacity than the practical, no belt, and much less powder capacity than the 7mm RUM or the 28 Nosler.

If you need a smith to do it, we can do the work or I believe the Chou Bros also have the reamer.

Research the 7LRM (Long Range Magnum) If you want to run the heavies, after all the research I did, it seemed like the best answer. Most velocity with the best balance of powder capacity.

Cheers
Shane
EM Precision Rifles
 
7 STW is about the minimum to make the 3000 with the heavier 7mm bullets, and you'll need at least a 26" barrel to do it. The 7-300 WM (aka 7mm Yukon/7x66 Randle) will be a little slower. Can always throttle down a 7 RUM (aka 7 Imperial Magnum) a little. Easier to get brass for too. There really is no free lunch, you need case capacity and barrel length to burn the powder and make the speed. - dan
 
dero338 said:
Maybe 7RUM


It may seems little dumb, but if build a 7mm barrel burner in order to launch high BC bullets at high speed, it would not worth jump 338LM?
Click to expand...
I have thought about getting another 338 Lapua, but the efficiency of the 195 is hypnotizing, it's sitting at .755G1 BC and launching it around 3000 does a very impressive number at 1000 plus. It's quite a pill, and a lot less recoil, still considering shooting without a brake. I was also considering a med weighted hunting rifle, so just trying to weigh all my options and this caught my eye. Also, the Lapua pills are quite pricey I found when I was shooting one, but it's still in the running. I haven't done a lot of looking at them lately to be honest, maybe they are more reasonable than I remember.
 
Have you looked at the 28 Nosler cartridge ?
I am just staring to play with it so no chronograph work yet, but it seems like it might be close to a 7 STW that I had for a while.
Hopefully it will move a 175 gr. load at decent speed..
 
duncansuds said:
I have thought about getting another 338 Lapua, but the efficiency of the 195 is hypnotizing, it's sitting at .755G1 BC and launching it around 3000 does a very impressive number at 1000 plus. It's quite a pill, and a lot less recoil, still considering shooting without a brake. I was also considering a med weighted hunting rifle, so just trying to weigh all my options and this caught my eye. Also, the Lapua pills are quite pricey I found when I was shooting one, but it's still in the running. I haven't done a lot of looking at them lately to be honest, maybe they are more reasonable than I remember.
Click to expand...

If you want a hunting set up for LR, I would go 30cal... I am breaking granite rocks at 800m with the 230gr Bergers from my 308 FTR rifle.

With addn powder and speed, the impact energy would be far more impressive. Yes, it will recoil much more BUT that is a sure sign that the receiving end will also see more energy.

The real appeal to me with the 195's is retained velocity... Yes, we can get 3000fps at a high cost but how much do you actually loose if ONLY going 2800 or 2900fps?

It takes alot of powder, wear and tear to gain an extra 100fps and in the bigger scheme of things, I would rather go a bit slower and have a consistently accurate rig that fits most rifles, then a hot rod that needs custom everything or is a PITA to make work.

For big but not crazy big, the 28 Nosler is an interesting option.. Pricey but stuff is becoming available. I like the idea of using a 300WM case.. bit more powder then the 7RM and relatively easy to set up. So it only goes 2900fps.

Oh well,

Jerry
 
a 7saum with a 28" pipe will hit 3000 with a 180gr Berger, 7mm Rem Mag 3100 fps, an STW/28Nosler should be in the neighborhood of 3200

7mm practical should split the diff. between the RM & STW/28N. If you can get 3150 with a 180gr, should be right close to 3000 with a 195gr EOL
 
I have a 7-300. I used a separate throating die to be able to keep all the bearing surface of the 180 Berger in the case neck while touching the lands. I'll be able to chase them as the throat erodes and still have lots of bearing surface in the case neck. I didn't do a tight neck reamer and accuracy is still great. Loaded rounds fit in a rem 700 bdl mag just fine
27 inch 9 twist tube gets me 3120 fps with no pressure signs and very small extreme spreads using H-1000 and fed 215's.

I doubt you'd get to 2500 rounds though

I have some 195's sitting here that I have yet to load for but I wouldn't see 3000 fps being a problem. There is still room left in the case with h-1000 and 180's so I think you'd be best to find a slower powder to fill more of the case for the 195's

I believe Nathan Foster changed the shoulder angle on the 7mm practical version so my die set up wouldn't work for you and you would likely require custom dies for the practical version and that's why I kept the 300 mag shoulder.

I use 300 win mag bushing dies to neck down and the 300 win mag body die when needed but since all I had for brass when I started was nosler brass I'm only seeing about 3 reloads before the primers pockets are loose. Needless to say I won't be using nosler brass for anything ever again.
I use a forester 7 stw seating die

I run prvi brass in a 300 mag and so far it's been great
 
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If you go to a stw case I don't think loaded rounds will fit in the mag if that's important to you plus the velocities you read about are likely obtained with long freebore which isn't conducive to shooting vld Bullets accurately usually. If you short throat it you'll probably reach pressure sooner leaving a lot of space in the case which probably won't help with extreme velocity spreads.

In my opinion the 300 wm case is about perfect for a long range 7mm bore.

Another great option is a 300 wm using 215 bergers but the bullets are more expensive
 
.284 said:
I have a 7-300. I used a separate throating die to be able to keep all the bearing surface of the 180 Berger in the case neck while touching the lands. I'll be able to chase them as the throat erodes and still have lots of bearing surface in the case neck. I didn't do a tight neck reamer and accuracy is still great. Loaded rounds fit in a rem 700 bdl mag just fine
27 inch 9 twist tube gets me 3120 fps with no pressure signs and very small extreme spreads using H-1000 and fed 215's.

I doubt you'd get to 2500 rounds though

I have some 195's sitting here that I have yet to load for but I wouldn't see 3000 fps being a problem. There is still room left in the case with h-1000 and 180's so I think you'd be best to find a slower powder to fill more of the case for the 195's

I believe Nathan Foster changed the shoulder angle on the 7mm practical version so my die set up wouldn't work for you and you would likely require custom dies for the practical version and that's why I kept the 300 mag shoulder.

I use 300 win mag bushing dies to neck down and the 300 win mag body die when needed but since all I had for brass when I started was nosler brass I'm only seeing about 3 reloads before the primers pockets are loose. Needless to say I won't be using nosler brass for anything ever again.
I use a forester 7 stw seating die

I run prvi brass in a 300 mag and so far it's been great
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I would be very interested in getting your thoughts on the 195's when you start playing.

That is excellent, thanks for all the replies guys, some great insight and information. I think the 300 shoulder would be great as well, I was likely confused as to which was which, I thought the practical kept those shoulders, either way, this is what I was hoping for. I know now 2500 is a pipe dream, but what I may do is get two barrels, same brand, same batch, get em cut at the same time. That way I can chase that throat until it's past its practical life, then when that time comes, swap out the barrel, and have a very close starting point for the next one and with any luck, run same loads with same basic accuracy and carry on.
 
.284 said:
If you go to a stw case I don't think loaded rounds will fit in the mag if that's important to you plus the velocities you read about are likely obtained with long freebore which isn't conducive to shooting vld Bullets accurately usually. If you short throat it you'll probably reach pressure sooner leaving a lot of space in the case which probably won't help with extreme velocity spreads.

In my opinion the 300 wm case is about perfect for a long range 7mm bore.

Another great option is a 300 wm using 215 bergers but the bullets are more expensive
Click to expand...

I am still weighing that option too, just having a a current infatuation with 7mm's for some reason. I could always swap to 300 barrel if I am tired of the 7 too! No losing...

I still want a repeater, so yes, that's important
 
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I think the biggest drawback to the 28 Nosler is the brass. First it is Nosler brass and second it is $4/piece. My 338 Lapua brass is cheaper than that. You could go all the way to a 7/300 Norma or a 7/338 Improved and go crazy for less money per load and blow it out of the water. Plus is runs 10g or so more powder than the LRM and about 15g more than the 7/300 or Practical without a really significant payoff for the money. 28 Nosler really missed the mark in my opinion. It is just easier for the novice handloaders that don't want to fireform.

Another option would be the 7mm Rogue. (improved 7 Rem Mag) Very cool cartridge.
 
So I tried some 195's with H-1000.

My chamber was cut for 180's as I described already. I seated the 195's 10thou off and they still fit in the mag. I started low and worked up in .3 increments. I started to see pressure at about 2950 fps. I think that if you cut your chamber with a bit more freebore than I have you could reduce pressure signs and reach 3000fps. How much freebore though I'm not sure. I'm also not sure if the 195's will shoot good if they have a bit of a jump to the lands

I haven't tried any other powders yet but the only other slow powder I have on hand is retumbo and I believe you would have a better case fill percentage with something even slower as there is a bit of room left in the case with H-1000.

My barrel is a 9 twist as it was built for the 180's and as such the Berger twist calculator says I'm losing 7% of the potential BC but they were stable and grouped well in the ladder test.

I ran some numbers based on 2900fps with the 195's and compared them to my 180's at just over 3100fps. There's not a lot difference but I'm a bit better off staying with the 180's for long range shooting.

If you went with the 8.3 twist they recommend and realize the full BC potential of the 195's and have a longer throat than I do with a slower powder you may very be able to best the performance of the 180's for long range work.

Hope that info is useful to you.
 
Very useful, I appreciate the data. I have been beating the crap out of the top 6 7mm bullets over 175 grs and comparing all to the 300 mag over 175gr ....still fighting myself on this one. That 195 keeps pulling me back to it. Not that I plan on dropping g animals at 1000+, but I like the idea of the hammer of Thor at those ranges. I was thinking of barreling a little long (27") to start and slightly reducing my load, giving me the ability to chase it back and still hold roughly the same results as I scale back to 26" as erosion occurs. Don't know if this is a realistic option. I would do this for either the 7mm or 300win as they both suffer from shorter life in the throat.

Apparently these 195's are a little more forgiving than many Bergers before them. I am thinking a 8.5 twist for 7mm and a 1-10 for 300
 
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