7/300 PRC - vs 7 PRC, is this the way it should have been done?

[Article 4]

In 2019, well before Hornady released their version of the 7 PRC - we did a wildcat project taking a 300 PRC and necking it to 7mm. 7/300 PRC. We took the 300 PRC bushing die and resized the neck, thats it.

Initially it was to run the high BC 195 Berger for LR hunting but then found the 180 Berger was a good fit too, along with the 175 ELDX and others.

Data: Pics are of the 175 and 180 - ran out of 195 before I could take a comparative pic. Data is on a BAT machine action, Bart 25 inch 8 twist bbl - Kahles Scope
195 Berger - 77.7 grains H1000 at .003 off lands = 3032 fps
180 Berger - 78.6 grains N565 at .006 off lands = 3177 fps
175 ELDX - 79.5 grains of RL 25 at .012 off lands = 3220 fps

None of these show pressure signs at the node. We can go faster and ran the 175 ELDX all the way up to 3290 and began to see pressure. They are however all <.50 MOA.

An average for like bullets, we are seeing up to 240 fps faster speeds than the 7PRC, as would be expected with case capacity.

I dont want the Hornady version. Feel like running this set up for hunting primarily, I can run faster for hunting and have plenty of case capacity to do whatever I want without sacrificing anything.

 

[hiker270]

Wouldn't this be similar to a 28 Nosler?

 

[Article 4]

Wouldn't this be similar to a 28 Nosler?

Kinda - different parent case though

 

[199p]

I have had 3x 7-375r (24" 2x 26") great round but too big to run a suppressor.
My last one shot the 180eldm @ 3150 from a 26" and was built on a tikka m695 action.
My 300 norma mag made it obsolete 225eldm @ 3050

I have built a 20" 7prc to run a suppressor. This will be my main traveling rifle and will run factory ammo. I haven't got my hands on it yet but its due very shortly. Should make for a better allrounder.

 

[Article 4]

I have had 3x 7-375r (24" 2x 26") great round but too big to run a suppressor.
My last one shot the 180eldm @ 3150 from a 26" and was built on a tikka m695 action.
My 300 norma mag made it obsolete 225eldm @ 3050

I have built a 20" 7prc to run a suppressor. This will be my main traveling rifle and will run factory ammo. I haven't got my hands on it yet but its due very shortly. Should make for a better allrounder.

Nice rig. I had a 7/338 NM improved for a while and it was fun pushing the 195 Bergers at almost 3500 FPS but it wasnt really a manageable every day hunting rig
I have hunted with this a lot. Very manageable and very good in the wind running HIGH BC bullets extra fast.

 

[199p]

nice man, was going to build one of them but the 300 was all done and way to good of a deal,
when that barrel is toast it will be a tough decision

 

[Article 4]

nice man, was going to build one of them but the 300 was all done and way to good of a deal,
when that barrel is toast it will be a tough decision

What I like about this rig is if I wanted to, change the bbl and its a 300 PRC! Like 2 guns in one!

 

[MCC335]

Thanks for the info on the 7-300 PRC! I have a pre-fit from PVA being delivered tomorrow.

I am seeing 3-5 thou of runout on a few dummy rounds I made last night. Any suggestions?

SAC FL die with their .311 shoulder bushing
21st century 0.283 mandrel
195 seated at 3.680 (don’t know the COAL to the lands yet)

With and without the mandrel and also before and after seating the bullets, the runout was always 3-5 thou.

Are you neck turning these?

Thank you!

 

[MCC335]

BTW.. with the SAC die, I don’t get the doughnut which I would expect from a typical FL bushing die. The entire neck is being resized.

 

[wind gypsy]

How is 7/300 PRC different than 7LRM? Should be pretty dang close? Seems like brass availability and being a c-unt hair less overbore than 28 nosler are the possible benefits vs the 28?

None of hornady's cases are that overbore so it makes sense they didn't use the bigger case and kept the 7PRC in a similar velocity window with heavies to the 6.5 and 300.

 

[Bluefish]

I believe they touched on this when they did the podcast on the 7 prc. Don’t remember now, but there was a reason they didn’t just make a 7/300prc.

 

[MCC335]

The case of the 7LRM was shortened by around 65thou I believe compared to the 300PRC.

Biggest benefit for me of the 7/300 PRC is that I don’t need to purchase proprietary brass and dies from gunwerks. I am already set up for 300 PRC so all I needed to do was buy a 7mm bushing.

 

[Article 4]

Thanks for the info on the 7-300 PRC! I have a pre-fit from PVA being delivered tomorrow.

I am seeing 3-5 thou of runout on a few dummy rounds I made last night. Any suggestions?

SAC FL die with their .311 shoulder bushing
21st century 0.283 mandrel
195 seated at 3.680 (don’t know the COAL to the lands yet)

With and without the mandrel and also before and after seating the bullets, the runout was always 3-5 thou.

Are you neck turning these?

Thank you!

I am using 200 pieces of adg brass and resizing in two stages. I do neck turn and prefer .0015 chamber expansion when fired so turned necks to accommodate

A bit of stress on brass so after first loads I anneal and double check measurements. Now on 2nd round and brass has settled in and resizing is consistent.

 

[Article 4]

I believe they touched on this when they did the podcast on the 7 prc. Don’t remember now, but there was a reason they didn’t just make a 7/300prc.

what I did was too easy. Simple. Hornady makes no money with my changes.

The reason IMO is due to Hornady marketing and profit expectations. Significantly more opportunity for profitability making a whole new round.

 

[MCC335]

I am using 200 pieces of adg brass and resizing in two stages. I do neck turn and prefer .0015 chamber expansion when fired so turned necks to accommodate

A bit of stress on brass so after first loads I anneal and double check measurements. Now on 2nd round and brass has settled in and resizing is consistent.

Thanks again for the info. I am using ADG brass as well, I have preferred the thinner neck for the 300 PRC vs Lapua.

I will load a few the way I have them to sight in/barrel break-in and then see what my fired expansion is.

What bushing sizes are you using in the 2-step? Maybe 2 steps will help lessen my run-out.

 

[Slick8]

IMO the 7-300 PRC is a duplicate of a 28 Nosler. A great round for 180-195s but hot and hard on barrels. The one nod I'll give the PRC over Nos is Lapua brass.
There's Lapua then there's the rest.

I feel like the factory 7 PRC is a great round but I do wish they had simply used the already great gunwerks 7 LRM. It has that true 7 RM case capacity without the belt and body taper plus it has a really long neck.

I get why the big H went where they did with the 7PRC and no one can argue with their product development / marketing over the past dozen or so years. But, I feel like with heavies most people will be stomping on the PRC pretty hard to attain the velocity they're after. It's a little more than a SAUM but not truly RM capacity.

Hopefully, Lapua will add it to the line up, that will be a game changer.

 

[Article 4]

IMO the 7-300 PRC is a duplicate of a 28 Nosler. A great round for 180-195s but hot and hard on barrels. The one nod I'll give the PRC over Nos is Lapua brass.
There's Lapua then there's the rest.

I feel like the factory 7 PRC is a great round but I do wish they had simply used the already great gunwerks 7 LRM. It has that true 7 RM case capacity without the belt and body taper plus it has a really long neck.

I get why the big H went where they did with the 7PRC and no one can argue with their product development / marketing over the past dozen or so years. But, I feel like with heavies most people will be stomping on the PRC pretty hard to attain the velocity they're after. It's a little more than a SAUM but not truly RM capacity.

Hopefully, Lapua will add it to the line up, that will be a game changer.

Yeah, it is the same thought process as 28 Nos but diff parent case. When I did mine the 7PRC wasn't released yet. Also, PRC was "designed" to have more neck and shoulder space than Nos at Saami so theoretically, running the super long 195 berger is ideal this way. I wanted something to run that bullet specifically that I didnt have to buy special wildcat brass during covid and beyond.

I get a bit more performance for hunting using the 195 than the shorter cased 7PRC as released.

 

[MCC335]

I am using 200 pieces of adg brass and resizing in two stages. I do neck turn and prefer .0015 chamber expansion when fired so turned necks to accommodate

A bit of stress on brass so after first loads I anneal and double check measurements. Now on 2nd round and brass has settled in and resizing is consistent.

What bushing sizes are you using during initial neck down?

 

[Article 4]

Typo in previous
Went to go to shop and look at my bushings - 300 PRC is around a 334 bushing standard so the get to the 7mm is used 3 and not 2 at .326 then .318 then .311 final

 

[MCC335]

Typo in previous
Went to go to shop and look at my bushings - 300 PRC is around a 334 bushing standard so the get to the 7mm is used 3 and not 2 at .326 then .318 then .311 final

Thank you, sir! The info is greatly appreciated!