3,570 fps with 150 gr bullet

[Unertl Eyebrow]

Just posting stw data...
New Hart 30"length, 1 in 9" twist barrel produces 3,570 fps with 78.5 gr of 7828 using a 150 grain Nosler accubond. Decent pressure, good accuracy. After some load work and occasional practice it should give me 10-15 years of use as a hunting rifle. I have 65 rounds through it.
That is a lot of speed. I guess the 28 nosler and 7mm RUM would do it too. But I never saw anyone post those speeds.

 

[Mallardhammer]

I have a Sako 75 that wears a 26" 1-9 Krieger in 7stw. I had the 150 accubond running about 3400 and very accurate, I can't remember what I ran it up to or if that was max. it's been awhile, I believe I was fireforming from 8mm Remington? Anyways, love the STW. And that's some good speed your getting. I'd like to know how an accubond at shorter distances performs in the mid 3k's on game. Never got to test it.

 

[crystalgayleguy]

Just posting stw data...
New Hart 30"length, 1 in 9" twist barrel produces 3,570 fps with 78.5 gr of 7828 using a 150 grain Nosler accubond. Decent pressure, good accuracy. After some load work and occasional practice it should give me 10-15 years of use as a hunting rifle. I have 65 rounds through it.
That is a lot of speed. I guess the 28 nosler and 7mm RUM would do it too. But I never saw anyone post those speeds.

awesome

 

[26Reload]

Wow.....you might test that bullet on water jugs ro see what its potential to blow up might be.....cant be many hunting bullets that can handle that much force and create good wound channels....

 

[J E Custom]

Just posting my experiences with the 7 STW.

Mine was a 31" barreled 1885 high wall browning for the short receiver and a single shot. it also had a 1 in 9 twist and was chambered for a 140 grain bullet, (I wanted to match the A Square loading of 3500 ft/sec in a flat shooting hunting bullet).

I worked up past 3800 ft/sec with the 140, but around 3750, accuracy dropped off because of the twist rate. All but the mono metal bullets shed there jackets from two much RPM. I settled on the best compromise of accuracy and trajectory around 3700 ft/sec.

Obviously it was a laser and often made shots over 800 yards. the downside of this blazing speed was barrel life and it never made 400 rounds before it was toast. By this time the 7 rum had came out and I wanted to duplicate the velocity with a 160 to 180 class bullet, so I built the 7 RUM on a 28" barrel and easily reach 3600 with great accuracy and decided to stay in that neighborhood to save the barrel. So far so good with just over 200 rounds through it, the bore scope shows little signs of throat erosion.

The much larger case capacity cartridge can handle much more docile powders. and doesn't beat the cases up as bad. I still have a 7 STW setup for hogs and it gets limited number of shots as a hunting rifle and the loads are 150 grain bullets @ 3550 ftsec and has everything I need/want in a hog rifle.

7828 was designed for the 7 stw and is a great powder, but I ended up preferring H 5010 (No longer made) so now I use H 50 BMG. Your load is a very hot load and if you can back off just a little maybe you won't eat up your barrel and cases as fast as i did.

J E CUSTOM

 

[Unertl Eyebrow]

I wonder about the bullets too. I never used an Accubond before. But it's the only one advertised as "unlimited" for the maximum velocity. I have used 78.5 gr 7828 for a long time. I would not make it any hotter but it has always been ok in my rifles.
Does anyone know if there a standard for estimated velocity loss or gain as temperature rises or lowers? (For big cased cartidges). Not the ballistics but actual muzzle velocity. How much slower is a 20 degree round vs an 80 degree round?

From Nosler's site
Accubond
Minimum Velocity: 1800 fps (549 mps)
Maximum Velocity: Unlimited

 

[J E Custom]

I wonder about the bullets too. I never used an Accubond before. But it's the only one advertised as "unlimited" for the maximum velocity. I have used 78.5 gr 7828 for a long time. I would not make it any hotter but it has always been ok in my rifles.
Does anyone know if there a standard for estimated velocity loss or gain as temperature rises or lowers? (For big cased cartidges). Not the ballistics but actual muzzle velocity. How much slower is a 20 degree round vs an 80 degree round?

From Nosler's site
Accubond
Minimum Velocity: 1800 fps (549 mps)
Maximum Velocity: Unlimited

Temperature over 80 degrees and up seems to be the worst about increasing the velocity, but below 50 can also reduce the velocity a smaller amount. I don't think this is linear.

I would also think that the Accubond would work in the STW (They were not available at the time).
Don't know about the unlimited velocity though, all bullets have there limit if accuracy is the goal.

J E CUSTOM

 

[yobuck]

Im using 78 gr of 7828 with the 162 Hornady BTHP match bullet in my 7x300 Weatherby.
Ive tried 150s but find the 162s work better at the longer distances.
They also work better as for flat trajectory than the 180 Berger out to about 1200 yards.
Which is as far as i care to use the 7x300 on deer.
Im using second generation bullets now more than 40 years old, and having a lower BC than the original version BC of .725.
One thing for sure though, the Unertle scopes were the very best for eye brow cuts. lol

 

[jasonco]

Just posting my experiences with the 7 STW.

Mine was a 31" barreled 1885 high wall browning for the short receiver and a single shot. it also had a 1 in 9 twist and was chambered for a 140 grain bullet, (I wanted to match the A Square loading of 3500 ft/sec in a flat shooting hunting bullet).

I worked up past 3800 ft/sec with the 140, but around 3750, accuracy dropped off because of the twist rate. All but the mono metal bullets shed there jackets from two much RPM. I settled on the best compromise of accuracy and trajectory around 3700 ft/sec.

Obviously it was a laser and often made shots over 800 yards. the downside of this blazing speed was barrel life and it never made 400 rounds before it was toast. By this time the 7 rum had came out and I wanted to duplicate the velocity with a 160 to 180 class bullet, so I built the 7 RUM on a 28" barrel and easily reach 3600 with great accuracy and decided to stay in that neighborhood to save the barrel. So far so good with just over 200 rounds through it, the bore scope shows little signs of throat erosion.

The much larger case capacity cartridge can handle much more docile powders. and doesn't beat the cases up as bad. I still have a 7 STW setup for hogs and it gets limited number of shots as a hunting rifle and the loads are 150 grain bullets @ 3550 ftsec and has everything I need/want in a hog rifle.

7828 was designed for the 7 stw and is a great powder, but I ended up preferring H 5010 (No longer made) so now I use H 50 BMG. Your load is a very hot load and if you can back off just a little maybe you won't eat up your barrel and cases as fast as i did.

J E CUSTOM

I still have lots of H5010, from my 7STW/27" Stilen, days and it still smells good to go. I got great velocity with 160-175gn bullets with it, the issue was, it's was very sooty and 10+ shots would be a great string, but the accuracy went to crap. H1000 would work, until H50BMG came along.

 

[MagnumManiac]

Just posting my experiences with the 7 STW.

Mine was a 31" barreled 1885 high wall browning for the short receiver and a single shot. it also had a 1 in 9 twist and was chambered for a 140 grain bullet, (I wanted to match the A Square loading of 3500 ft/sec in a flat shooting hunting bullet).

I worked up past 3800 ft/sec with the 140, but around 3750, accuracy dropped off because of the twist rate. All but the mono metal bullets shed there jackets from two much RPM. I settled on the best compromise of accuracy and trajectory around 3700 ft/sec.

Obviously it was a laser and often made shots over 800 yards. the downside of this blazing speed was barrel life and it never made 400 rounds before it was toast. By this time the 7 rum had came out and I wanted to duplicate the velocity with a 160 to 180 class bullet, so I built the 7 RUM on a 28" barrel and easily reach 3600 with great accuracy and decided to stay in that neighborhood to save the barrel. So far so good with just over 200 rounds through it, the bore scope shows little signs of throat erosion.

The much larger case capacity cartridge can handle much more docile powders. and doesn't beat the cases up as bad. I still have a 7 STW setup for hogs and it gets limited number of shots as a hunting rifle and the loads are 150 grain bullets @ 3550 ftsec and has everything I need/want in a hog rifle.

7828 was designed for the 7 stw and is a great powder, but I ended up preferring H 5010 (No longer made) so now I use H 50 BMG. Your load is a very hot load and if you can back off just a little maybe you won't eat up your barrel and cases as fast as i did.

J E CUSTOM

Hi J E,
Would really like those loads you are using with H50BMG. The only Bullets I have been able to get here are 150gr BT's.
Other bullets are on order.
Do you have loads for heavier pills with H50BMG?

Cheers.

 

[Unertl Eyebrow]

 

[yobuck]

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Assuming the rifle scope attached to the handle on the Spacemasters is used as a finder scope?
A soda straw size tube glued to that works well for that also.
Some brackets are designed with the scopes on a 45 deg angle instead of verticle as these are, which allows the factory version sight to remain. These would have had sights, whereas the older grey ones did not.
Some guys i know use the handle for mounting their rangefinder.
As for barrel legnth when using 7828, i have 2 7x300 Wetherbys.
One is a heavy sporter version similar to the one shown on a 700 action and has a 27" barrel. The other is built on a Rem 40x action and has a 30" barrel. Both are 9 twist. Velocity is the same in both guns using the same 78 gr load with the 162 Hornady. I use 3400 for my chart, and the results pretty much concur with that.

 

[J E Custom]

Hi J E,
Would really like those loads you are using with H50BMG. The only Bullets I have been able to get here are 150gr BT's.
Other bullets are on order.
Do you have loads for heavier pills with H50BMG?

Cheers.

I am hesitant to give out my loads because I made changes to the reamer design to get more velocity @ design pressure. I change the lead angle and the freebore was increased over .100 thousandths. the bullets are seated to 3.550 and pressures were very manageable. I also used a 36" drop tube to get bulky powders in the case. It was a lot of trouble, but nothing is free when going after velocity.

There are starting loads in different manuals using H 5010 and 50 BMG so they would be safe in your rifle. I have not tried many of the new powders because I have a very accurate load and don't believe in messing with the combination of something that works very well.

I will tell you that the Nosler Partition performed very well also even if the BC of that bullet are not as good as boat tailed bullets and were my go to bullets for under 500 yard shots. The Ballistic tips were very explosive at under 500 yards, the Accubonds should cure that Issue.

As stated before, the bullet becomes the critical component in high velocity loading's.

J E CUSTOM

 

[J E Custom]

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Being a flat lander, I really like the looks of your place. The rifle ain't bad ether

J E CUSTOM