1050fps out of an 8” barrel with a 500gr slug?

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Sealtee
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1050fps out of an 8” barrel with a 500gr slug?

Post by Sealtee » Sat Oct 04, 2014 12:22 am

New guy here with a question; I am going to submit another Form 1 here shortly for a bolt action, big bore sub gun. My plan would be to “only” shoot .458” 500gr cast slugs (Such as the Lee 500gr Sp). Since SBR’s are not legal in my state, it will be internally suppressed. I am guessing that I should be able to get this cast projectile moving to 1050fps in 8 inches of barrel with the push of a “458 Bushmaster” (Yeah I know, there is no such thing as a 458 Bushmaster :shock: .)

My question, before I go and cut this barrel, do you think that 8 inches of rifled barrel is enough runway to get 1050+fps with this cartridge?

FWIW, I have a 27-1/2” long barrel that is 1.3” diameter and I am planning to cut a 19” length of this barrel for this project. (Leaving me 8-1/2” of barrel for another project! :mrgreen: ) I THINK that 8” of rifled barrel and 11” of suppressor should do it. What do you think?

-Regards

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daviscustom
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Re: 1050fps out of an 8” barrel with a 500gr slug?

Post by daviscustom » Sat Oct 04, 2014 1:19 pm

Sounds very similar to an ongoing project of mine. I decided to not do an integral so I could get more utility out of the form 1 on other hosts, but my original plan was an integral bolt action bullpup....now it is just a bolt action bullpup with a threaded barrel. Suppressed it should be about the same overall length as a compact rifle, roughly 37-40" OAL. (Haven't decided on the final design for the suppressor)

I think you should be ok with that length barrel, but their are probably folks here..... or definitely on the 458Socom forum that can say for sure. It has been a while since I was thinking short barrel, but IIRC I was originally going with 9" before I changed plans.
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BCJ
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Re: 1050fps out of an 8” barrel with a 500gr slug?

Post by BCJ » Sat Oct 04, 2014 2:21 pm

The 8" barrel should work fine. I built and integral 458 Socom using an eight inch barrel and it works great. I use the 405 gr soft points at 1000 fps

Sealtee
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Re: 1050fps out of an 8” barrel with a 500gr slug?

Post by Sealtee » Sat Oct 04, 2014 6:10 pm

BCJ wrote:The 8" barrel should work fine. I built and integral 458 Socom using an eight inch barrel and it works great. I use the 405 gr soft points at 1000 fps
Hey BCJ,

Did you build an AR or a bolt gun? What powder do you use for the 405gr at 1000fps? Diameter and length of your suppressor?
Thanks for the info!

-Regards

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Re: 1050fps out of an 8” barrel with a 500gr slug?

Post by BCJ » Sat Oct 04, 2014 11:00 pm

I use 15 grains of TrailBoss in the Socom. Mine is a bolt gun guilty on a savage action.
The suppressor is 1.625" o.d. And overall length of the integral barrel is just shy of 18".
Image

Sealtee
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Re: 1050fps out of an 8” barrel with a 500gr slug?

Post by Sealtee » Sun Oct 05, 2014 1:07 am

Hey BCJ,

Thanks for the info and the picture! Good to know that you are having good luck with such a fast powder, I bet it’s quiet! Nice looking shooter too! Sort of what I have in mind. Mine though will be built on an M48 Mauser action (Because I have one laying around!) and in fact I just came in from cutting and threading the barrel and fitting it to the action! :mrgreen: I will chamber it sometime this week after I make up some dummy rounds.

Thanks for your help!

-Regards

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daviscustom
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Re: 1050fps out of an 8” barrel with a 500gr slug?

Post by daviscustom » Sun Oct 05, 2014 8:58 am

Here is a link to a thread where a guy was helping me out with quick load....it is all figured for a 16.5" barrel, but he will probably tweak it for a shorter barrel for you if you ask nicely. I am using the same 500 gr mold.

viewtopic.php?f=111&t=123650
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Sealtee
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Re: 1050fps out of an 8” barrel with a 500gr slug?

Post by Sealtee » Sun Oct 05, 2014 2:37 pm

Thanks Davis C,

Even though that info was created based on a 16.5” barrel assumption, it is actually very informative and helpful to me with an 8+ inch barrel. Knowing that the faster powders burn within the first couple of inches or so, most of the velocity that is obtained with the faster powders in a longer barrel, will also be obtained in the 8 inch barrel.

FWIW, I plan to experiment with Red Dot, Tite Group and Blue Dot because I already have them. I expect that BD may be the best choice of the powders I have. From your data, Unique might very well be the go to powder with this barrel, bullet, cartridge combination along with the speed limit.

Thanks again for sharing your thoughts!

-Regards

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Re: 1050fps out of an 8” barrel with a 500gr slug?

Post by mpallett » Thu Sep 17, 2015 4:44 pm

Where did you get with this?

I have a bolt gun with a 12" barrel and use the RedDot and it works well. It DOES NOT work well in my AR with the 8.5" barrel.


Sealtee wrote:Thanks Davis C,

Even though that info was created based on a 16.5” barrel assumption, it is actually very informative and helpful to me with an 8+ inch barrel. Knowing that the faster powders burn within the first couple of inches or so, most of the velocity that is obtained with the faster powders in a longer barrel, will also be obtained in the 8 inch barrel.

FWIW, I plan to experiment with Red Dot, Tite Group and Blue Dot because I already have them. I expect that BD may be the best choice of the powders I have. From your data, Unique might very well be the go to powder with this barrel, bullet, cartridge combination along with the speed limit.

Thanks again for sharing your thoughts!

-Regards
Over weight Telco guy with a FFL/07 for hire :)

Sealtee
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Re: 1050fps out of an 8” barrel with a 500gr slug?

Post by Sealtee » Thu Sep 17, 2015 7:20 pm

I ended up with a 21 inch barrel that was back bored 11" leaving 10" of rifled barrel. I have not really worked much on the Form 1 suppressor part, but I did fit this barrel to an M-48 Yugo Mauser action with a Boyds thumbhole stock. I chambered this for what I call a 458 Bushmaster using a slightly expanded 450 Bushmaster cases. I use my 450 Marlin dies for re-loading. I throated the chamber so that I could seat the boolit long to take up a good portion of the mag for proper feeding. It feeds nice.

I started the loading process by doing some calculating and guess-timating and decided to use 800X powder because of the fairly light density (To help fill the case) and a burn rate only a little slower than Unique. After starting with a fairly light charge I worked my way all the way up to 15.0 gr to give me a very consistent velocity of 1070 fps using a powder coated Lee 500gr non-gas checked boolit.

To date we have only taken it out a few times and I gotta say, this one is stinkin’ FUN to shoot!! Yeah it’s gotta little bit of shove but really nothing to whine about. My 2 sons and I went through 100 rounds in a sitting and this thing just left us just smiling! With open sights this thing seems to hit the steel targets at 50 yds with ease. This fall I will likely get back to this project by finishing the K’s and threading the end of the barrel/suppressor. For now it is just plain fun to shoot just as it is! :D

-Regards

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Re: 1050fps out of an 8” barrel with a 500gr slug?

Post by Wicked » Thu Sep 17, 2015 9:00 pm

458 Socom chambered 8.5" barrel

Lee cast 500gr bullet seated to 2.260" OAL

22.0 gr Hodgdon Lil' Gun

70% case fill. 98% burn. 23K psi chamber pressure. 5.7K psi muzzle pressure.

1073 fps velocity. 1277 ft/lbs energy.
https://www.facebook.com/wickedweapons

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