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Howa 1500 7 PRC Build

dankcincy

dankcincy

Private
Minuteman
Nov 15, 2020
61
34
Cincinnati
Its going to be a blueprinted Howa 1500 with an LRI fitted K&P 28" MTU Contour 1:8 Left Twist with an Ultrdyne Apollo LR brake sitting in a Woox Exactus precision stock using the Vortex Strike Eagle 5-25x56 in a 30 MOA American Defense mount sitting on a 25MOA rail.

Out of the box this was a 300 Prc cambered rifle that I had minimal success with out at a mile using factory ammo. It came with a pencil barrel and I knew I would be changing it out so I never bothered buying dies for the 300Prc. I didn't know which direction I would be taking it so I didn't want to get too invested.

I've spoken with Ken at K&P and Eric at LRI. All I have to do it this point is get it boxed up and shipped out.




www.snipershide.com

7mm PRC

Oh I paid that without a second thought. Hornady brass is going straight in the trash, not even keeping it as a backup.
www.snipershide.com www.snipershide.com

hawkinsprecision.com

Reloading for 7 PRC - Hawkins Precision

Reloading 7 PRC - Learn how six different powders work in Hornady's new 7 PRC. Powders include H1000, N565, H4831SC, RL23, and Retumbo.
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7mm PRC: Complete ballistic data (recoil, trajectory, energy) – Backfire

backfire.tv backfire.tv

www.longrangeonly.com

7MM PRC Cartridge Guide - Long Range Only

DISCLAIMER: This is a guide. Everything listed within is for information purposes only. All loads should be worked up carefully. We have seen loads that require as much as two grains of charge weight adjustment from one powder lot to another. We have seen as much as five grains of powder...
www.longrangeonly.com www.longrangeonly.com

Peterson Brass 7mm PRC Unprimed Bulk Box of 250 - Graf & Sons

This is a Bulk package of Peterson Cartridge casings, they will not come in one of their plastic ammo boxes. Made in the U.S.A. Designed to fill the gap between 6.5 PRC and 300 PRC, the 7mm PRC follows in the footsteps of its older brothers. It fires long, heavy for caliber bullets, 160gr to...
www.grafs.com www.grafs.com

Dies

Shop Rifle & Shotgun Reloading Supplies | Dies | Bullets | Hulls | Wads | Powder - Precision Reloading

Shop online for shotshell and metallic reloading supplies, shooting supplies, metallic presses, rifle reloading components, shotshell reloading components, shooting accessories, rifle reloading brass and Bullets.
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21stcenturyinnovation.com

Expander Die Body (Expander Die Body: Standard with Ring- #904)

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Last edited:
@dankcincy, if you will allow me, I’ll provide my $0.02. I will start by saying that I don’t have any personal experience behind a 300 PRC. Maybe that disqualifies me, but I think not. This is opinion, not gospel.

I own a custom 7 PRC, and if starting over would do it again. I do know that recoil on a 300 is much more. Not sure how sensitive you are to recoil, but everyone will shoot a lighter recoil rifle better than heavy recoil.

The 7 is in a sweet spot in relation to bullet weight and efficiency. For the 7, you have either the 180 ELD-M, or the 190 A-Tip, two phenomenal bullets. Obviously there are other brands, but you mentioned Hornady brass, and I’m most familiar with their bullets. The 180 and 190 bullets are incredible as to wind drift and retained speed.

It seems that you are a target shooter, being you mentioned such distances. I think I would opt for the 7 in your situation. Lighter recoil, lower per round cost, more shootability, and a very balanced cartridge.

You can’t go wrong with either, but I think you’ll be more apt to spend more time behind the trigger on the 7.

Although it’s negligible, the two bullet choices I mentioned above have a higher BC for the 7 than the same bullets for the 300.

Not sure I’ve helped much, but trying to contribute what I can.
 
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@Schmo
I looked at those TL3s, those things are damn nice. I really like the ARC Coup De Grâce as well.
For the barrel I was thinking 28 or 30 to safely get a few more fps. Do you think that may be too much?
This will strictly be a bench rifle
 
I’m not real savvy on the longer barrel lengths, but I think 28” is the max I would go. The 7 does not highly react to barrel lengths. An average of 25-50 fps per inch on length is dropped when cutting down from 24”. Going with a 28” over a 24” may gain you 100 fps. I don’t know this and I’m guessing.
 
I need to adjust my question a bit, I think I'm pretty clear on what I'm going to as far as which cartridge to go with.

The question now is what length barrel, twist rate, and contour for the 7.

Looking at the projectile offers...
Sierra has a 197 and is calling for a 7.5tw
Berger 195 is calling for a 9tw
Hornady 190 is calling for an 8tw.

It appears that my options from K&P are a 7 and an 8. 9 I know is too slow for what I'm wanting to do.
The question would be, is 7 too fast?

Looking at the offerings in the 180-197 range, its seems that the theme is Hornady calling for an 8 and Berger calling for 9 with Sierra being the single one calling for a 7.5.

I did see someone somewhere say something along the lines of them thinking they were having stabilization issues with the 195 using an 8.

Edit:
Using these two calculators and using 300k RPM and 3000fps as the upper limits, it seems that with the 7tw, I would be flirting with disaster the entire time so an 8tw would be the safer option to go with. 7.5tw seems to be about perfect but I'm not seeing that as an option.
bergerbullets.com

Twist Rate Stability Calculator​

Our newly updated Twist Rate Stability Calculator not only tells you what your SG is, but it also lets you know if you are reaching your optimized BC.
bergerbullets.com
bergerbullets.com

Bullet Spin Rate Calculator - Savvy Calculator​

Learn how to calculate the spin rate of bullets with our Bullet Spin Rate Calculator. Input muzzle velocity and barrel twist rate, and instantly get the Bullet Spin Rate in RPM.
savvycalculator.com
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@dankcincy , go no slower twist than an 8. 7.5 may be better, but like you said it may be hard to find. I wonder if anyone does a gain twist from an 8 to a 7.5? 🤔
 
@Schmo
I haven't asked them but from what I've seen, Bartlein would most likely do it. I asked LRI about doing a left hand gain twist and the response was that K&P doesn't do gain twist barrels but I could get a left hand twist from them. They said that they would gladly fit a Bartlein if I sent it to them though. Last I saw, Bartlein was something like 8 months out... so being that gain twist barrels being used with modern projectiles is more theoretical and subjective than fact, for me personally, its not worth the delay.
I would like to try one at some point though.
 
Schmo said:
@dankcincy, if you will allow me, I’ll provide my $0.02. I will start by saying that I don’t have any personal experience behind a 300 PRC. Maybe that disqualifies me, but I think not. This is opinion, not gospel.

I own a custom 7 PRC, and if starting over would do it again. I do know that recoil on a 300 is much more. Not sure how sensitive you are to recoil, but everyone will shoot a lighter recoil rifle better than heavy recoil.

The 7 is in a sweet spot in relation to bullet weight and efficiency. For the 7, you have either the 180 ELD-M, or the 190 A-Tip, two phenomenal bullets. Obviously there are other brands, but you mentioned Hornady brass, and I’m most familiar with their bullets. The 180 and 190 bullets are incredible as to wind drift and retained speed.

It seems that you are a target shooter, being you mentioned such distances. I think I would opt for the 7 in your situation. Lighter recoil, lower per round cost, more shootability, and a very balanced cartridge.

You can’t go wrong with either, but I think you’ll be more apt to spend more time behind the trigger on the 7.

Although it’s negligible, the two bullet choices I mentioned above have a higher BC for the 7 than the same bullets for the 300.

Not sure I’ve helped much, but trying to contribute what I can.
Click to expand...
Click to expand...

Perceived recoil on many 300prc rifles is more pleasant than 7prc. Obviously more powder and such will make the 300prc more recoil on paper.

But perceived recoil, while subjective, is absolutely a thing. Different types of cases produce different feeling recoil. IMO, a 300prc is more pleasant to shoot than a 300wm. And depending on the build (stock and such), I find 300prc recoil to be more pleasant than 7prc. The 300prc is more a straight push where the 7prc is more "snappy."

For reference, we build a lot of both. Just last week we chambered and built five 7prc rifles and a couple 300prc.
 
That’s the thing. My rifle scoped, but empty was right under 9 lbs. In a 9lb rifle, it’s very shootable with my brake. I’m not arguing about the 300, as I’ve heard they aren’t bad to shoot. But I am saying that the 7 is very manageable, especially since you will have a heavy build
 
Rio Precision Gunworks said:
Perceived recoil on many 300prc rifles is more pleasant than 7prc. Obviously more powder and such will make the 300prc more recoil on paper.

But perceived recoil, while subjective, is absolutely a thing. Different types of cases produce different feeling recoil. IMO, a 300prc is more pleasant to shoot than a 300wm. And depending on the build (stock and such), I find 300prc recoil to be more pleasant than 7prc. The 300prc is more a straight push where the 7prc is more "snappy."

For reference, we build a lot of both. Just last week we chambered and built five 7prc rifles and a couple 300prc.
Click to expand...
This is not the first time I've heard this. Frank said the same thing. Not to derail the thread, but I've been entertaining a 27 Nosler build as a result.
 
@dankcincy, that’s what I’m already saying. I run a 7 PRC that’s a 9 lb rifle for hunting. Took three deer with it in Montana this season. In a 9lb hunting rifle with a brake, recoil is very manageable. I shot a doe at 370 yards off of a Sirui tripod. Stayed in the scope and watched her drop. If recoil is that manageable in a 9lb hunting rifle, you’ll be far better off with your heavy target build
 
357Max said:
This is not the first time I've heard this. Frank said the same thing. Not to derail the thread, but I've been entertaining a 27 Nosler build as a result.
Click to expand...

We are considering having a reamer made with 300prc just necked down to 7mm. For recoil comparison to normal 7prc as well as see what kind of performance we can get.

But the recoil effect, I have seen across the board. Obviously it's much less recoil, but I prefer the recoil of a 6cm to a 6dasher. Push vs a snap. Neither matter in terms of spotting.....just a personal preference.
 
Rio Precision Gunworks said:
We are considering having a reamer made with 300prc just necked down to 7mm. For recoil comparison to normal 7prc as well as see what kind of performance we can get.

But the recoil effect, I have seen across the board. Obviously it's much less recoil, but I prefer the recoil of a 6cm to a 6dasher. Push vs a snap. Neither matter in terms of spotting.....just a personal preference.
Click to expand...
You could rent a 28 Sherman reamer if you just wanted to try one. Pretty sure that has a 40 degree shoulder & less body taper though.
 
@Schmo I just had a nice chat with Ken at K&P about barrel length and twist. He suggested a 28" and 8tw so that's what I'll be going with. I did ask him about the 7.5tw and he said that while it is an option, you're starting to play with that ragged edge and risking a projectile coming apart in the right conditions.
I also asked him about the gain twist and he said that he doesn't mess with it but a left hand twist is doable.

I then spoke with Eric at LRI for about the third time and ironed out the final details of it all.
All that's left now is box it up and get it in the mail. By the time the weather breaks, I should have it back and be ready to start working up loads for it. :D
 
Sounds awesome! I’m anxious to hear what results you get on load work-up. Are you having it chambered to SAAMI spec or will you have it throated a little long to be able to seat bullets out a little ways?
 
Well shit!!! LOL
I didn't even ask about any of that.
I'll call Eric back real quick, stand by.....

He didn't answer. I'll look into it a bit and ask him later.
My understanding is that SAAMI spec allows for the heavies, Is this not accurate
 
It does allow for heavies, but I’m not sure how far the 190s will protrude into the case. It handles 180s just fine. I was just curious since it’s a target build and not a hunting rifle if you might lengthen the throat. See what he thinks. He’ll know far far better than I
 
I did get ahold of Ken again, he basically said that its a bit of a complicated question that I need to discuss with Eric at LRI.
Long story short of what he said is that you want to keep it as short as possible for the longevity of the barrel but need it long enough to accept what you're trying to run.
 
@Schmo
I just remembered that I did ask Eric about that in one of our earlier conversations and if I remember correctly, he said that SAAMI allows for the longer 190, 195s. I will for sure ask him again though.
 
Gotcha. I know Hornady developed it around the heavy, high BC bullets. I just wasn’t sure what the situation was on the 190s and 195s
 
We have been stalling with this for a bit to see if they could get enough of a break in the work to finish up the fixturing and programming for the blueprinting but it doesn't look like it's going to let up for them anytime soon so we are going to go ahead with it without the blueprinting. Not the end of the world but it sure would of been cool to have the first one they did.
It's looking like the machine work will be completed this week and it will be handed off to the paint department for cerakote.
Hopefully it ships out sometime next week and I can get to finishing up what I need to do to fit it into the stock and then get some rounds thru it. 😁
 
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