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

[DaleW]

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 = 3132 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.

Do you recall what your OAL is with the 195?

Going by your numbers it seems like a guy could run a 22" tube and a can and still get the 195s above 3k. That would be dirty...

 

[Article 4]

Do you recall what your OAL is with the 195?

Going by your numbers it seems like a guy could run a 22" tube and a can and still get the 195s above 3k. That would be dirty...

I did a custom reamer with 225 freebore - COAL with 195 = 3.67
I do not recommend a 22" bbl. We are running a lot of powder. Shortest I would go with would be 24 and 25 or 26 is ideal.

 

[199p]

Do you recall what your OAL is with the 195?

Going by your numbers it seems like a guy could run a 22" tube and a can and still get the 195s above 3k. That would be dirty...

Im not so sure
From what i have seen in 7-375r that i had was something like 230fps difference from 23-3/4 factory tikka barrel to the 26" lilja barrel i had.

Only gained like 80fps going from 7remag to 7-375r from memory then longer barrel really took off.

 

[DaleW]

Im not so sure
From what i have seen in 7-375r that i had was something like 230fps difference from 23-3/4 factory tikka barrel to the 26" lilja barrel i had.

Only gained like 80fps going from 7remag to 7-375r from memory then longer barrel really took off.

Wow that's way more of a dropoff than I would expect.

 

[MCC335]

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 = 3132 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.

I’m sorry to bother you with more questions, but there is limited data on the 7/300 PRC and I trust your experience with it.

I am having difficulty reaching anywhere near your posted velocities and I am hoping you may have an idea or two.

I have ruined the primer pockets on about 25 new ADG brass so far. Moderately flat Fed 215, no tight lift, easy extraction.

Defiance Anti
28” Med Palma, Patriot Valley Arms
ADG Brass, New, .311 SAC Neck bushing, chamfer

195 EOL, 4th OL
Tried h1000, RL-26 and n570.
Best velocity with 75.8gr n570 - 3080fps, anymore and the brass is ruined.
Fired neck expansion is >0.0015

I have a 26” 300prc that can run 3020fps with Berger 215s and RL26 all day with 4x fired brass, also on a defiance anti. I am really scratching my head here. Any help would be greatly appreciated!!

 

[Article 4]

I’m sorry to bother you with more questions, but there is limited data on the 7/300 PRC and I trust your experience with it.

I am having difficulty reaching anywhere near your posted velocities and I am hoping you may have an idea or two.

I have ruined the primer pockets on about 25 new ADG brass so far. Moderately flat Fed 215, no tight lift, easy extraction.

Defiance Anti
28” Med Palma, Patriot Valley Arms
ADG Brass, New, .311 SAC Neck bushing, chamfer

195 EOL, 4th OL
Tried h1000, RL-26 and n570.
Best velocity with 75.8gr n570 - 3080fps, anymore and the brass is ruined.
Fired neck expansion is >0.0015

I have a 26” 300prc that can run 3020fps with Berger 215s and RL26 all day with 4x fired brass, also on a defiance anti. I am really scratching my head here. Any help would be greatly appreciated!!

My sincere apology. The Berger number is a mid typed figure. It should be 3032 and not 3132. I will go back and make the change

Looks like you are getting what you should with that barrel and set up.

The 570 giving you best velocities makes sense.

 

[MCC335]

Looks like you are getting what you should with that barrel and set up.

The 570 giving you best velocities makes sense.

Thank you for the information and for making the change!!

Brass is fire-formed, annealed and FL resized now with 0.311 bushing and 0.2825 mandrel. Maybe I will see some better velocity with the once fired brass.

I was using data for the 28 Sherman mag shown below as a reference. I figured I would get close to their published velocity given that I have 2 extra inches of barrel length.

Unfortunately, I can only hit 3090-3100fps with the 190 Atip and 77gr (Max) of N570… somehow they are running 80gr N570 with the 195 @ 3200

 

[MCC335]

EDIT:

Unfortunately, I can only hit 3082fps with the 190 Atip and 77gr (Max) of N570… somehow they are running 80gr N570 with the 195 @ 3167fps with a 2” shorter barrel