Anyone own a 7mm 300 Win Mag?

[Broz]

Yep, custom dies are in the cards. According to Kiff the sharp shoulder should nearly eliminate growth. At the pressures I plan to run I figure the primer pockets might open up before it needs FL or body resizing. For neck sizing I was planning to use Redding Type S bushing dies with the sleeve hogged out by my chamber reamer. Ditto the sleeve in a Redding Comp seater die.

Yep that will work. It's the body die that is hard and not a simple process to come up with.

Jeff

PS: for what it's worth Redding is not taking anymore custom die orders.

 

[barnesuser28]

Yep that will work. It's the body die that is hard and not a simple process to come up with.

Jeff

PS: for what it's worth Redding is not taking anymore custom die orders.

Jeff, we commented at the same time, look at my previous post.

 

[chuckhammer]

Yep that will work. It's the body die that is hard and not a simple process to come up with.

Jeff

PS: for what it's worth Redding is not taking anymore custom die orders.

Plan is to send the reamer and die sleeves to a friend who has a full machine shop and turn him loose. I'm a mechanical engineer and am OK with hand tools but am not a machinist. My magic is done on a computer rather than on a lathe or 5-axis mill.

BTW - Your efforts and those of Kiwinate are what convinced me to go with a 7-300WM cat. I read both your stories on various forums from the 2010-2011 time frame and was motivated hy the excellent results you guys had with 162-180 gr bullets in this case. I went with a touch of body taper reduction (.007) and the 37 deg shoulder to eek out a bit more capacity, be different, and limit case growth. Was going to do 40 deg but Kiff convinced me that 37 was shown to be optimal. That guy has an enormous amount of related knowledge he can pull right off the top of his head. That combined with his willingness to share his time and mind are an unbeatable combination for service.

Question - If I were to zip one of those stubby, thin-jacketed 100 or 110 gr bullets down range at >4k fps do you think they would hold together? Barrel will have a 1/8.5 to 1/9 twist.

 

[cummin_un_glued]

my smith said mine should be done in 4 more weeks...my McMillian stock is also slated to be done in Aug.... cant wait!

 

[AZShooter]

Regarding your desire to shoot a lightweight bullet:

The TTSX 110 Barnes or any other mono (does someone else make one?) would hold up to high velocity abuse. The 110 tnt speer and 100 gr sierra varminter wouldn't. I think the 120 nosler bt would hold up too. There are not many 100-110 gr 7mm bullets out there.

 

[Broz]

Question - If I were to zip one of those stubby, thin-jacketed 100 or 110 gr bullets down range at >4k fps do you think they would hold together? Barrel will have a 1/8.5 to 1/9 twist.

I would not use a Berger over 3400 with those twists. I think it would be asking for trouble. Plus I am not a small bullet fan, those little guys will loose speed as fast as they made it and the bullet with more cubic inches will motor past them down range. I think in terms of long range these days so the bigger bullets are better for me and what I do.

That said years ago I did build a 25-300 Wby and was sending 115 Bergers at over 3650 from a 10 twist. I didn't have any problems with it and the rifle is still killing white tails today, but does leave a big hole in them.
Jeff

 

[calib]

well another learning phase working with this rifle. i have 21 rounds through the barrel which mean little to nothing, because i got a wrong reading of oal length using just a sized down 300 win mag gauge for the hornady set up. my first 9 shots where jammed about 100 thousands, came home with a zeroed gun at least, did some measuring and talked to bill about what is going on, brass was fine, but bullets were going in too far, so i put a bullet in a fired case and shoved it in being all marked up with sharpie i could see where it was pushing it to, so i measured that and got 100 thousands less so i went 103 thousands shorter, took those out and fired them off and still had some issues, came home talked to bill about the gauge and then got a hold of brad and asked him to machine out one of my fired cases to make a clean gauge for me, got that done found out over all i was about 150 thousands jammed with the first 9. now i have a baseline to work from, but even with a sized piece of brass once fired i get resistance closing the bolt, so now we are thinking head space/ shoulder bump which i have never bumped any cases so this is all new. i also sent an e mail to where the reamer came from to try to get a diagram for measurements of my chamber. hope to get this all figured out with in the next few weeks and out shooting again. this gun doesn't kick any more than a 243 liking it so far.

in my pressure test which i am sure numbers are not worth much i went from 73-77 grains with no real pressure problems with velocities ranging from 3050-3222fps, with all 9 shots within 3" at 200 yards.

 

[chuckhammer]

well another learning phase working with this rifle. i have 21 rounds through the barrel which mean little to nothing, because i got a wrong reading of oal length using just a sized down 300 win mag gauge for the hornady set up. my first 9 shots where jammed about 100 thousands, came home with a zeroed gun at least, did some measuring and talked to bill about what is going on, brass was fine, but bullets were going in too far, so i put a bullet in a fired case and shoved it in being all marked up with sharpie i could see where it was pushing it to, so i measured that and got 100 thousands less so i went 103 thousands shorter, took those out and fired them off and still had some issues, came home talked to bill about the gauge and then got a hold of brad and asked him to machine out one of my fired cases to make a clean gauge for me, got that done found out over all i was about 150 thousands jammed with the first 9. now i have a baseline to work from, but even with a sized piece of brass once fired i get resistance closing the bolt, so now we are thinking head space/ shoulder bump which i have never bumped any cases so this is all new. i also sent an e mail to where the reamer came from to try to get a diagram for measurements of my chamber. hope to get this all figured out with in the next few weeks and out shooting again. this gun doesn't kick any more than a 243 liking it so far.

in my pressure test which i am sure numbers are not worth much i went from 73-77 grains with no real pressure problems with velocities ranging from 3050-3222fps, with all 9 shots within 3" at 200 yards.

Refresh my memory, is this a straight 7mm-300WM shooting 180 Bergers? Bbl length? Are you single-loading them or feeding from the mag? If the latter, the bullets could be slipping forward under recoil while still in the mag.

 

[calib]

Single load, 29" barrel, straight 7-300win 180 berg vld

 

[chuckhammer]

Single load, 29" barrel, straight 7-300win 180 berg vld

H1000, correct?

I'm looking forward to seeing what RL-33 can do in mine. Double-base so it's very high energy and also just about the perfect burn speed for compressed loads under a 180 in these cases. Likely going to bit a little temperature sensitive but we don't swing more than ~30F around here during the day, year round (65-95 deg). Gotta love South FL.

Of course, there are no large mammals for me to blast around here.......

 

[RockZ]

Just to let you know.
I am having much better results in my 7-300ai with Norma cases and retumbo.
For me.. retumbo out performed h1000 by a large margin.
Win cases have worked well also.
The Norma cases have the largest capacity followed by the win.
I wasted a lot of time with rws cases, while they are definitely quality cases..I found the capacity too small. I had pressure problems with much less velocity then the other cases..with much reduced loads.
That is with 162 and 180gr bullets

 

[chuckhammer]

Just to let you know.
I am having much better results in my 7-300ai with Norma cases and retumbo.
For me.. retumbo out performed h1000 by a large margin.
Win cases have worked well also.
The Norma cases have the largest capacity followed by the win.
I wasted a lot of time with rws cases, while they are definitely quality cases..I found the capacity too small. I had pressure problems with much less velocity then the other cases..with much reduced loads.
That is with 162 and 180gr bullets

Good info. I've got some Win brass necked down to 284 and figured it was the best combo of strength and capacity. Had heard Norma brass was dimensionally very consistent but a bit soft. I guess you'd found it to be nearly as strong as Win brass?

 

[RockZ]

Yes
My Norma brass is extremely consistent,has high powder capacity and has been as durable as win brass.
With 162 amax while fire forming brass with 83gr retumbo at 3.586"oal I'm getting 3500fps out of a 29" barrel with no bolt lift issues and very little case head expansion and no hard extractor marks.
The bolt cycles smooth and easy.
With rws brass and h1000 I was getting terrible pressure signs at 3050fps.
Not what I expected, but that is the way it played out.

 

[Broz]

Yes
With rws brass and h1000 I was getting terrible pressure signs at 3050fps.
Not what I expected, but that is the way it played out.

I have posted many times that with RWS brass in a 300 win case to need to back off 3 to 4 grains. It is due to the much lower case volume of the RWS. So did you try the loads with 180's and H-1000 in the Norma brass? I have always wanted to try the load in Norma or Lapua brass that has larger case capacity.

Jeff