Is the 7-08 a good cartridge for cast?

[Marlin Junky]

I've been considering a 7-08 with a 1:11" twist (6-grooves). Any opinions with respect to this combo? I want to shoot < 160 grain boolits, fast.

MJ

[Bullshop]

How fast? Over about 2400 fps you need a bigger case like a 280. Over about 2800 fps you need a bigger case like a 7mag. Over about 3000 fps you need a bigger case like a 7mm WBY or STW.

[HARRYMPOPE]

I shot my 788 carbine with cast a bit in the 1990's.i used the 287308 Lyman and the RCBS 168 Sil bullet.I used 4759 @ 1900-2000 and i got about 1 MOA.it shot just as well as the 788 308 carbine I owned at the time.I always wanted a Rem700V in 7mm-08.

George

[Marlin Junky]

How fast? Over about 2400 fps you need a bigger case like a 280. Over about 2800 fps you need a bigger case like a 7mag. Over about 3000 fps you need a bigger case like a 7mm WBY or STW.

Up to 2400 fps is fine. The heaviest boolit I would consider is the NOE 150, of which I have no knowledge regarding it's actual weight or suitability to a typical 7-08 chamber/throat.

MJ

[geargnasher]

I just built one and have pushed it to 2600 with room to spare using 135-grain boolits. H414/Win 760 worked very well.

Gear

[Bullshop]

You said 160gn boolits in you OP so that is what I was basing my thoughts on.
With 150s 2400 fps will be nearly right at top end.
I used a 700V 7mm/08 one year as my fur rifle and it was a very dependable combo for as far as I dared to shoot them.
My longest kill was 600 yards. I thought the shot was a mis and seemingly so did the coyote. He trotted off about 400 yards then just fell asleep.
On my return home that evening I went back on the ridge he was on just to try to figure how much I missed by as I thought I shot low. I was first surprised not to find a low bullet strike and then very surprised to find the coyote shot through both lungs with just a very small hole in and the same out. Shooting 140 Sierras starting at 2400 fps and at 600 yards on a coyote got zero expansion.

[Marlin Junky]

I just built one and have pushed it to 2600 with room to spare using 135-grain boolits. H414/Win 760 worked very well.

Gear

Would a PAC-NOR 6 groove be up to snuff? They're available in both 1:11 and 1:12 inch twists. Like I said, < 160 grains which eliminates all the heavier silhouette designs. I would also like to use the 140 grain Sierra for deer and antelope on the prairie... probably gonna go with a 23" long barrel.

MJ

P.S. Gear, would you be talking about Lyman 287346?

[1Shirt]

Just about all ctgs are good with cast--------if you are willing to work with them------cartridges and rifles are all female!
1Shirt!

[jhalcott]

The short neck CAN be a problem. IF the leade is long enough to handle the long bullets , you SHOULD be all right. I've used long bullets in my 7tc/u, 7-30, 7-08 and .280 over the years. Some times with surprising results and some dismal failures. YOUR alloy and powder choice will have a lot to do with results! What are your intended uses of this load??

[shotman4]

the Lyman 287 442 does very good in a rem 788 dont know about a hunter bullet, could file a metplate, or hp it

[Marlin Junky]

The short neck CAN be a problem. IF the leade is long enough to handle the long bullets , you SHOULD be all right. I've used long bullets in my 7tc/u, 7-30, 7-08 and .280 over the years. Some times with surprising results and some dismal failures. YOUR alloy and powder choice will have a lot to do with results! What are your intended uses of this load??

Is this what I can expect from most reamers:

55229

This is actually a longer ball-seat than a SAAMI 308W chamber and I want to use as many boolit molds as possible without going tighter than a 1:11" twist. I actually think a better configuration would be to decrease the throat angle 1-2 degrees while shortening the ball-seat.

MJ

[geargnasher]

Mine's a Savage barrel with a 9.5 twist and the pound cast looks just like the SAAMI drawing. I've been using the Lee boolit, but the front band has to be sized down to a slight taper to put the GC fully inside the neck.

Gear

[HARRYMPOPE]

You said 160gn boolits in you OP so that is what I was basing my thoughts on.
With 150s 2400 fps will be nearly right at top end.
I
Are you talking cast? My 788 carbine with my 125g deer load was @ 2800 and the 140 Nosler was about 2700.These were with H450 and showed no undue pressure even in the rear lugged rifle.


George

[Marlin Junky]

Are you talking cast? My 788 carbine with my 125g deer load was @ 2800 and the 140 Nosler was about 2700.These were with H450 and showed no undue pressure even in the rear lugged rifle.


George

Pretty sure he was, otherwise the vernacular, boolits wouldn't have been used.

Anyone have a 7mm SAUM?

MJ

[HARRYMPOPE]

The 7mm-08 has all the powder capacity you need for cast hunting loads, no need for a larger case. The 7 x 57 is actually bit better case design IIMHO

[Marlin Junky]

The 7mm-08 has all the powder capacity you need for cast hunting loads, no need for a larger case. The 7 x 57 is actually bit better case design IIMHO

I very much prefer the 757 case but was considering the 708 for two reasons:

1) Brass availability

2) I would probably need a customized 757 reamer to fulfill my cast boolits requirements. Here's the SAAMI version of a 757 chamber with its long, sloppy throat:

[felix]

MJ, I would select the full caliber boolit length first and foremost. Choose the case capacity to support 2400 fps with the slowest powder contemplated volume wise. Choose the neck length to fully support the bearing portion of the boolit. Insist zero freebore and 3 degree (or less) inclusive leade. Choose twist for boolit length and shape. Customize the reamer, knowing full well a close fitting chamber to the designed cartridge will require no more than 50 rounds of ammo for the life of the barrel. As the barrel leade enlongates, move the boolit out of the case. The barrel should last a lifetime, making the reamer and dies pay for themselves time and time again. ... felix

The more square the case design, the more the SEE conditions are favored. The more square the case design, the higher the average pressure is tolerated by both the gun and case. Condom BR rounds appreciate the square form which increases the powder's burn speed for best ignition while at the same time decreasing the flow of brass which can form the donut ring. Therefore, choose a sloping case form for better cast boolit selection over the long haul. ... felix

[stocker]

I'm not sure if the twist specified will stabilize a 160 grain boolit. A 1/12 twist 7 X 61 S & H has difficulty with some 160 grain J-bullets at 3000 fps but not all bullets of that weight. Bullet length is a factor in the 1/12. Short 160's will work in it. 1/10 in the same cartridge handles anything I throw in it. Not sure how cast boolits of that weight will respond.

[pistolman44]

Friend of mine won one at a gun bash with a 20" brl about 5 yrs ago and have taken deer, hogs and varments. Told me that It's his favorite gun'

[Marlin Junky]

Felix,

What's wrong with the .12" freebore associated to the 7-08 drawing in post #11? I would think it would mate nicely with a .285" diameter leade driving band and help alignment on something like RCBS 7mm-145 SIL or the NOE "Hunter" shown on the next page.

Regarding your suggestions, in other words, you're saying go with the 757 with a custom throat but I don't have any experience with custom reamers; and therefore, no confidence it'll work out properly. Can you draw a throat that would accommodate RCBS 7mm-145 SIL, the NOE Hunter and perhaps a Sierra 140 and/or a Hornady 139 all in a 2.9" magazine box?

MJ

[Marlin Junky]

I would think a 160 grain spire pointed J-bullet would need more twist than the design below even if it weighed 160-165 grains in a soft (heat treated) alloy.

MJ

[felix]

500-1000 rounds at 40K will give you the 0.12" freebore absolutely free of charge, and then you can let the boolit sit out further if and when needed. Let a longer case neck (no taper) give you the up-front freebore you are asking. Get the barrel and action trued up front. ... felix

[Marlin Junky]

Felix,

So that's a 757 neck approx. 0.39" long and the throat should start right at the mouth, by stepping down to .285/286" and tapering to the groove diameter (.284") at a rate of 1 to 2 degrees? Kinda like this 280, correct?:

55327

I don't want a configuration that'll dictate deep seating of 139-145 grain jacketed bullets.

MJ

[fatnhappy]

I collaborated with Blammer on the 7mm Hunter design. Let's just say it was wrought with the 7-08 in mind.

I have the Saeco 071, RCBS 145, RCBS 168, 2 different 287308s, a saeco 070, a 287448, the lee soupcan, the NOE 7mm Hunter and a couple other. The hunter shoots as well, or better than any of them.

ymmv

[DanWalker]

I shoot a soupcan boolit seated over 16 grains of 2400 for a powerful accurate practice load. For hunting, I load a 140 grain partition over IMR 4064 or Varget. Everything I shoot with this rifle just falls down and dies. The 7mm08 is a fabulously underrated hunting round. Guess my bull elk last year (236 yards) didn't read gun rags.....

[felix]

MJ, neck the case for the longest bearing projectile. When playing with any long projectile, must assure magazine clearance. ... felix

Yeah, the 280 throat appears 'mo betta' for hot loads over a longer period of time. In fact, that is a good one. ... felix

[Marlin Junky]

MJ, neck the case for the longest bearing projectile. When playing with any long projectile, must assure magazine clearance. ... felix

I'm not sure I understand what you are saying Felix. What do you mean by "neck the case for the longest bearing projectile"? If I do decide to go with the 757 with a modified throat, I want to be able to use standard resizing dies. Are you saying the neck diameter needs to be changed along with the throat? If that's the case, my decision is hands down, a 708.

MJ

[felix]

Going standard is always the cheapest way out. I was thinking you were thinking up a dream gun of sorts. ... felix

[geargnasher]

If you order a custom reamer, go ahead and make the neck any length you desire (within reason) and form brass from .270 Winchester or similar, trim, ream, finish turn, and you'll have it. The other option is standard neck and poke the weight up into the bore silhouette-style, which reaches a point of diminishing returns with high-velocity nose support. Build on a long-action Savage and no worries about COAL with 7x57 or 7-08.

If it helps, my 7-08 with a SAAMI-spec chamber would put the check and two full lube grooves of the Soupcan inside the case. Also be mindful that there are at least two different throat designs for the 7x57, most of the modern ones are per your drawing but not always.

Gear

[Marlin Junky]

Also be mindful that there are at least two different throat designs for the 7x57, most of the modern ones are per your drawing but not always.

Gear

Super, [smilie=b: ...so would modifying the throat of a SAAMI 757 reamer to spec out like the the 280 Remington reamer (posted earlier) gain me anything in terms of compatible mold selection? I don't want to go with a long action... in fact, I've already got a short stainless M77 for this project. BTW, I'm not married to the 7mm idea, I just want to get something lighter/handier than my Pre-64 '06 that shoots at least as well and preferably better (i.e., more accurately beyond 2000 fps).

MJ

P.S. After looking at the spec's again, I see why Felix was talking about redoing the 757's neck... yeah, the 757 has more issues than it's worth... at least for my purposes right now.

[Marlin Junky]

If it helps, my 7-08 with a SAAMI-spec chamber would put the check and two full lube grooves of the Soupcan inside the case. Also be mindful that there are at least two different throat designs for the 7x57, most of the modern ones are per your drawing but not always.

Gear

Gear,

So the COL with the 7mm "Soupcan" is about 2.56"? That provides for a lot of boolit outside the case (i.e., long throat) and you say it shoots fantastic? :D

MJ

[geargnasher]

NO. I said the Soupcan would put the gas check and two full lube grooves inside the neck of my 7-08 with a SAAMI chamber. I shoot the regular production Lee 135-grain bore-rider in it, but it doesn't fit the throat angle at all (like almost all Lee rifle designs). I correct this by reshaping the front bands in a nose-first sizer.

Gear

[Marlin Junky]

I shoot the regular production Lee 135-grain bore-rider in it...

Gear

Oh yeah, bummer... I was too distracted when I wrote that.


NO. I said the Soupcan would put the gas check and two full lube grooves inside the neck of my 7-08 with a SAAMI chamber.

Gear

The gas check and two full lube grooves would equal .357" of the .882" overall length. The difference of .525" would be ahead of the case mouth yielding a COL of 2.035" + .525" or 2.56". Where am I going wrong here?

MJ

[Marlin Junky]

I have the Saeco 071, RCBS 145, RCBS 168, 2 different 287308s, a saeco 070, a 287448, the lee soupcan, the NOE 7mm Hunter and a couple other. The hunter shoots as well, or better than any of them.

fatnhappy,

Got any pics of groups and/or dead animals you care to share? :)

MJ