300 PRC update

[DAVETOOLEY]

COAL 3.730" with a 225 about .010" off.

One thing you do need to do with virgin brass. Expand necks and chamfer . Because of the way Hornady trims their brass there is a bit of ring on the case mouth. In some chambers it's enough to cause an interference fit.

 

[MOUNTIC]

COAL 3.730" with a 225 about .010" off.

One thing you do need to do with virgin brass. Expand necks and chamfer . Because of the way Hornady trims their brass there is a bit of ring on the case mouth. In some chambers it's enough to cause an interference fit.

So it would be correct to say that with the factory 225 Hornady ammo at 2.685 in your specific rifle you would have about a 55thou jump to the lands. And prob much more so with the 212s?

So this would be about max that you would do if you were only planning to run the 225s and needed the extra case capacity? It seems there is plenty of room in the case? and would you need to seat them that far out unless running them really hot? Just curious as I have no experience with the round.

 

[MOUNTIC]

For anyone interested, I Just pulled a bullet out of a 225 factory round and measured the powder. 75.2 gr. Maybe h1k. I don't know.

 

[DAVETOOLEY]

For anyone interested, I Just pulled a bullet out of a 225 factory round and measured the powder. 75.2 gr. Maybe h1k. I don't know.

Not sure why they would use a different powder.

 

[DAVETOOLEY]

So it would be correct to say that with the factory 225 Hornady ammo at 2.685 in your specific rifle you would have about a 55thou jump to the lands. And prob much more so with the 212s?

So this would be about max that you would do if you were only planning to run the 225s and needed the extra case capacity? It seems there is plenty of room in the case? and would you need to seat them that far out unless running them really hot? Just curious as I have no experience with the round.

I shoot the 212's at mag length. 3.700" or thereabouts. I have not determined how much jump they had. They were shooting about an inch at 200. Killed everything I shot at with them.
I am getting a reamer with a shorter throat for those that want it.
Hornady has to engineer safeguards in their designs. Too many stupid people out there. Sometimes they resemble that remark with ammo that's a bit too hot for some guns. If you can't get to the lands pressures have a difficult time spiking and that's what gets people into trouble.

 

[MOUNTIC]

Thanks Dave,

I think the reamer you have now sounds like it will be just fine for my barrel. Thank you again.

 

[ForeverZ01]

Does anyone have headspace gauges I can borrow/ rent/ buy from them?

 

[DAVETOOLEY]

Does anyone have headspace gauges I can borrow/ rent/ buy from them?

PM sent

 

[nick338]

So how many different reamers are available at this point?

 

[DAVETOOLEY]

So how many different reamers are available at this point?

SAAMI is all I know about. That hasn't changed from the 300 AI days. Anything else would be a special.

 

[j741]

If you’re looking to buy new headspace gauges

The 300 PRC gauges are made on a special order basis only. Cost is $60 each with a production time of 2-3 weeks. Payment at the time the order is placed is required.

Thanks for your interest in our products.

Ann Snyder-Manson


Dave Manson Precision Reamers
8200 Embury Road
Grand Blanc, MI 48439 USA
1-810-953-0732 (tel) 1-810-953-0735 (fax)
www.mansonreamers.com

 

[nick338]

SAAMI is all I know about. That hasn't changed from the 300 AI days. Anything else would be a special.

Any idea why the factory ammo would jam into the lands with one reamer but not others?

 

[DAVETOOLEY]

Any idea why the factory ammo would jam into the lands with one reamer but not others?

I don't have a clue.

 

[W54/XM-388]

Just ordered a set of gauges from Manson this afternoon.
Hopefully with all the interest in the .300 PRC they should be making them a bit more often before long.

 

[Taken Out Slak]

I'll first be shooting it from an AI AXMC once I get the barrel in, but I'm really interested to see how it would work as a long range hunting rifle in the 8 to 10 pounds range that could also represent itself nicely at the range and long distance targets shot slowly.

Any further thoughts on this hunting rifle set up? Something portable but w longer range potiential using the 212s.

 

[DAVETOOLEY]

Mine's is on a Remington 700. I built it decades ago with a 7MM and 338 barrel based on the 8X68S case. Those barrels may never see action again.
If I need a 338 again I'll go to a tougher 30 cal bullet in the PRC. If that isn't big enough I'll take a 375 H&H. I shot a big Eland in SA this year with 212's. No problems.

 

[j741]

PVA has informed me they can do either a 8tw or a 10tw, but not a 9 unless it's cut rifled at a $125 extra cost. Recommendations? I'm leaning towards 8.

 

[MOUNTIC]

PVA has informed me they can do either a 8tw or a 10tw, but not a 9 unless it's cut rifled at a $125 extra cost. Recommendations? I'm leaning towards 8.

Then I would go 10. Not going to speak for DT here, but he mentioned this to me below on the proof blanks I was going to send him. A 9.4 or a 10 twist...

We're splitting hairs here but the 9.4 would be marginally better if you are going to shoot Berger 230's. Anything lighter/shorter and the difference is on paper not the target. I have a 9.5 on one rifle shooting 225's. If it was a 10 or a 9 I seriously doubt I could shoot/see the difference. In fact all the work done with AI and this round, we used 10 twist barrels. I shot to 2K with 225's then with no problems.

 

[j741]

Then I would go 10. Not going to speak for DT here, but he mentioned this to me below on the proof blanks I was going to send him. A 9.4 or a 10 twist...

We're splitting hairs here but the 9.4 would be marginally better if you are going to shoot Berger 230's. Anything lighter/shorter and the difference is on paper not the target. I have a 9.5 on one rifle shooting 225's. If it was a 10 or a 9 I seriously doubt I could shoot/see the difference. In fact all the work done with AI and this round, we used 10 twist barrels. I shot to 2K with 225's then with no problems.

I can understand not much difference between 9.4 & 10. I'm admittedly not an expert, but seems like difference between 8 & 10 would be a bit more. Looking a other posts in the thread I do see mostly mentions of 9 twist with a sprinkling of 8 & 10. Definitely will appreciate @DAVETOOLEY 's input on it.

 

[Taken Out Slak]

Mine's is on a Remington 700. I built it decades ago with a 7MM and 338 barrel based on the 8X68S case. Those barrels may never see action again.
If I need a 338 again I'll go to a tougher 30 cal bullet in the PRC. If that isn't big enough I'll take a 375 H&H. I shot a big Eland in SA this year with 212's. No problems.

Thanks for the info. What about practical hunting length barrels? I read you mentioned min 26 in another post. Do we loose to much of the cartridges potential going much shorter for hunting? Like enough to be better off just using a diff caliber? I am in Alaska so close, long, and really long, distances and big, very big, and not so big animals are all very probable circumstances.
The main prob is I just cant seem to go back to the ole off the shelf hunting rifle after shooting precision rifles so always looking for the best combo.

 

[nick338]

I can understand not much difference between 9.4 & 10. I'm admittedly not an expert, but seems like difference between 8 & 10 would be a bit more. Looking a other posts in the thread I do see mostly mentions of 9 twist with a sprinkling of 8 & 10. Definitely will appreciate @DAVETOOLEY 's input on it.

I was originally going to use a 9.5 twist but I'm at sea level in the northeast so tack on cold temperatures as well and I decided the 9 twist was a better option. Rather have a little more of a safety margin to handle all conditions. I'm not sure going faster is a benefit as I've been there and done that with a 7 SAUM and did not experience the benefit I was hoping for.

The new Sierra 230 says 1-8 on their website but I don't think I would twist a barrel to shoot 1 specific bullet with the possibility of over-spinning a majority of the other bullets in common use.

This is pure speculation on my part but as a bullet with a long secant nose slows down to transonic speeds, forward pressure on the nose causes some pitching and yawing and it would seem that the faster it's rotating the more torque is applied causing instability. The more I try to learn on the subject the more I feel this was happening with the 183 Sierra I was shooting from the 7 twist SAUM.

 

[DAVETOOLEY]

Thanks for the info. What about practical hunting length barrels? I read you mentioned min 26 in another post. Do we loose to much of the cartridges potential going much shorter for hunting? Like enough to be better off just using a diff caliber? I am in Alaska so close, long, and really long, distances and big, very big, and not so big animals are all very probable circumstances.
The main prob is I just cant seem to go back to the ole off the shelf hunting rifle after shooting precision rifles so always looking for the best combo.

I have a 25" barrel on my rifle. My comments were directed towards the majority of people on this site. Long range shooters. Hunters always make compromises to fit their specific situation.

 

[DAVETOOLEY]

Twist rates. I have a 9.5 on one rifle shooting 225's and a 10 on my hunting rifle. I'll never shoot 225's and up in that rifle. Maybe a heavy premium hunting bullet. They will all work in a 10.
This is just me but I don't want the faster twists on a hunting rifle. I'm splitting split hairs here but they do torque more making them harder to shoot.

 

[InkedIan]

As far as twist goes in regards to accuracy... I've ran 208 amaxs and 210 smks from a 9 twist for a while and they shoot awesome. Now from a 300wm they would probably only need a 11 twist or a 10 twist at the most to stabilize and be accurate yet they shoot great from a 9 twist. What I'm saying based off of my experience don't be afraid to go a twist faster than what you need as long as the bullet you're shooting can handle it.

 

[nick338]

Twist rates. I have a 9.5 on one rifle shooting 225's and a 10 on my hunting rifle. I'll never shoot 225's and up in that rifle. Maybe a heavy premium hunting bullet. They will all work in a 10.
This is just me but I don't want the faster twists on a hunting rifle. I'm splitting split hairs here but they do torque more making them harder to shoot.

Yes they do as I can attest to this even on a 17lb rifle shooting prone. It torqued noticeably.

 

[nick338]

If you're unsure then use the Berger twist rate calculator and plug in the variables. Use the worst case shooting conditions you think you will find yourself in and run with it.

 

[Kickin45]

Ok guys, please don’t team me for asking, but 7 pages is a bit mich to read.
What do I need to do to convert my PTG 300wm action, AIAT into 300PRC?
Thanks

 

[W54/XM-388]

Ok guys, please don’t team me for asking, but 7 pages is a bit mich to read.
What do I need to do to convert my PTG 300wm action, AIAT into 300PRC?
Thanks

If you have a .300 Winmag rifle already, for single feed, you pretty much just need to get a new barrel.
Then you'll need to see about your magazine system and chassis to see if it will fit the long factory loads or if you need changes there.

The AIAT rifle won't work with the .300 PRC as it's a short action and you'll need a long action and magnum boltface.
You could however get your AIAT to shoot the 6.5 PRC with just a barrel change.

 

[Hondo1]

If you have a .300 Winmag rifle already, for single feed, you pretty much just need to get a new barrel.
Then you'll need to see about your magazine system and chassis to see if it will fit the long factory loads or if you need changes there.

The AIAT rifle won't work with the .300 PRC as it's a short action and you'll need a long action and magnum boltface.
You could however get your AIAT to shoot the 6.5 PRC with just a barrel change.

I don’t know of any mag bolts the fit the short action AI’s. If there is one I’d be first in line.

 

[Kickin45]

I meant AICS 2.0. LA.
Don’t know why I put AIAT.

 

[Kickin45]

So all I’d need is a barrel swap?
Is anyone producing the 300PRC barrels?

 

[DAVETOOLEY]

So all I’d need is a barrel swap?
Is anyone producing the 300PRC barrels?

Yep
I've been doing barrels for it for quite a while now.
Many others are tooled up for it also.

 

[Kickin45]

Great. My next question is suppression. Will my SiCo Omega 300 handle this round safely?

 

[DAVETOOLEY]

Great. My next question is suppression. Will my SiCo Omega 300 handle this round safely?

I would defer to them but your only talking about a 5-7% increase in powder capacity. I wouldn't expect any problems.

 

[nick338]

Ok guys, please don’t team me for asking, but 7 pages is a bit mich to read.
What do I need to do to convert my PTG 300wm action, AIAT into 300PRC?
Thanks

What is the maximum length cartridge you can fit in your magazine?

 

[PowerstrokeOBX]

Ordered a proof 1-8 for 198 and the PRC.

 

[j741]

Ordered a proof 1-8 for 198 and the PRC.

Where was that pricing available?

 

[j741]

For those interested in the 3.85" length 300WM AICS mags, MDT has them on sale today for $45 ea.

https://mdttac.com/collections/poly...tal-magazines-long-action?variant=45859520198

 

[MOUNTIC]

For those interested in the 3.85" length 300WM AICS mags, MDT has them on sale today for $45 ea.

https://mdttac.com/collections/poly...tal-magazines-long-action?variant=45859520198

Picked a few up earlier today to test out. Didn't want to get too many as there is little feedback on these things as they are relatively new. Well see how they do.

 

[putput30]

What will the COAL be for the 300 prc with a flatline 198 grainer? Will it be able to be mag fed in a 3.85 mag?

 

[nick338]

What will the COAL be for the 300 prc with a flatline 198 grainer? Will it be able to be mag fed in a 3.85 mag?

What ever your barrel wants it to be. You would have to develop the load and seat the bullet accordingly.

 

[briang7511]

Yes they do as I can attest to this even on a 17lb rifle shooting prone. It torqued noticeably.

please describe the torque. Not sure if i have experienced this.

 

[b6graham]

What ever your barrel wants it to be. You would have to develop the load and seat the bullet accordingly.

Hes asking a pretty basic and understandable question. With a saami reamer and a flatline basically at the lands(give or take 30 thou), how long would it be.

 

[nick338]

please describe the torque. Not sure if i have experienced this.

Sure. No muzzle brake shooting prone with decent amount of pressure into the shoulder, the rifle not only has a decent amount of muzzle jump but torques to the left also. I believe this to be more pronounced as bullets get heavier and velocity and twist rates become faster.

With a right hand twist the the rifle is trying to counteract what the bullet is doing as it travels down the bore and exits the muzzle. Heavier bullet and faster twist makes it more noticeable.

 

[Milepost]

Hes asking a pretty basic and understandable question. With a saami reamer and a flatline basically at the lands(give or take 30 thou), how long would it be.

Have never loaded using the flatline bullets but given the unique hourglass shape of the flatline bearing surface area that would not be too easy to answer... To take full advantage of the 198 you would need the freebore adjusted accordingly and then the COAL would be around 3.86". Which of course is too long for a CIP Mag.

 

[Bradu]

Have never loaded using the flatline bullets but given the unique hourglass shape of the flatline bearing surface area that would not be too easy to answer... To take full advantage of the 198 you would need the freebore adjusted accordingly and then the COAL would be around 3.86". Which of course is too long for a CIP Mag.

Why would you set it up and adjust the freebore for 3.86 if mags are 3.85? That makes absolutely no sense when you are gaining .010". If you are going to set them up for single feed then I would make sure to set it up better than that.

As far as getting a reamer setup for them, I would ask Warner tool or Patriot Valley Arms to assist with that.

 

[Milepost]

You pretty much answered your own question...

Ask Warner to send you a sample bullet and adjust accordingly to work with a Saami spec reamer and your CIP magazine length. I think you will find that the max will be somewhere close to 3.7"

Just as nick338 said set up the bullet to what your barrel wants it to be and then do your load development. If it feeds thru the CIP mag internal length of 3.75-3.77" Great!! If not, adjust accordingly or shoot the Berger or SMK instead.

The cartridge is new so there is very little load data available. Why don't you just give Dave Tooley a call next week and ask him directly?

 

[Bradu]

You pretty much answered your own question...

Ask Warner to send you a sample bullet and adjust accordingly to work with a Saami spec reamer and your CIP magazine length. I think you will find that the max will be somewhere close to 3.7"

Just as nick338 said set up the load to the your barrel wants it to be and then do your load development. If it feeds thru the CIP mag internal length of 3.75-3.77" Great!! If not, adjust accordingly or shoot the Berger or SMK instead.

The cartridge is new so there is very little load data available. Why don't you just give Dave Tooley a call next week and ask him directly?

For someone that has never loaded them you are rather amusing. That was a rhetorical question but thanks for the answer lol. If someone is wanting a reamer made for then then I would hope they would buy a box of bullets to send out as a sample to their Smith rather than waste a company's time asking for a free bullet.

 

[b6graham]

No one here has an ogive measurement for a 198 flatline compared to a 225 ELDM or 215 or 230 hybrid? Doesnt matter if it's a 300WM or 300NM. It's all relative anyways

 

[DAVETOOLEY]

No one here has an ogive measurement for a 198 flatline compared to a 225 ELDM or 215 or 230 hybrid? Doesnt matter if it's a 300WM or 300NM. It's all relative anyways

I have some Flatlines. I won't have time to make up a dummy round until probably Tuesday.