KH_Outdoors
Well-Known Member
Oh yes... they usually do. From what I've seen so far though, I dont think this 7-300 barrel is going to be very picky. We'll just see where we land on velocities.
Last edited:
7-300 PRC Build & Load Development!
- Thread starter KH_Outdoors
- Start date
Oh yes... they usually do. From what I've seen so far though, I dont think this 7-300 barrel is going to be very picky. We'll just see where we land on velocities.
KH_Outdoors
Well-Known Member
Load Development Update
Still refraining from cracking open the N570! I decided to start with H1000 & N565 as they're both extremely stable clean burning options. Then, decided to add in Retumbo & N568 just to see if it might favor a slower burn rate. These are just baseline charge weight ladders below and my notes from each. When I start Load Development on "new" rifles I favor coarse testing right away. I will pick the bullet I want to shoot and a couple powders to run up to pressure before any fine testing. I'll aim at the same point at 100 yards, shoot 1-2 rounds, mark them and repeat while never letting the barrel get hot. This achieves a few things for me on new combinations. Firstly: safe charge weight windows to work with. Second: overall grouping, and also noting if certain charges land together. Generally speaking that can be an accuracy node. By comparing overall groupings of different powders and looking for accuracy nodes it tells me what powder is most likely going to group best with said bullet. Kinda quick & dirty but I've had high success doing it this way without wasting time and components!
H1000
75 - 2964.6
76 - 3012.2
77 - 3055.9
78 - 3083.4
79 - 3135.3 - Ejector mark
80 - Discontinued
Notes: Good group overall with charge weights 76-79 gr clustered together.
N565
75 - 2964.5
76 - 2996.0
77 - 3043.0
78 - 3082.4
79 - 3123.2 - light Ejector mark
80 - Discontinued
Notes: Ok grouping, not quite as clustered up like H1000 but charges 75-76 bunched together then also 78-79 again.
Retumbo
76 - 2963.7
77 - 3021.8
78 - 3057.9
79 - 3099.9
80 - 3135.0
81 - 3169.8 - light Ejector mark
Notes: Good grouping overall with charges 78-81 all clustered up together. Best velocities before pressure of all powders tested.
N568
77 - 2890.0
78 - 2947.4
79 - 2978.4
80 - 3019.6
81 - 3037.1
82 - 3070.3
83 - 3123.4 - light Ejector mark
Notes: Ok grouping with charge weights 80-83 all nearly touching in one cluster. Best case fill of all powders tested.
Based on the testing so far, I'm going to do some group testing with Retumbo and maybe H1000 or N565 with the goal in mind of getting close to 3100 fps with 180's
. Every powder tested is showing really good potential in the 3000-3100 fps range!
Still refraining from cracking open the N570! I decided to start with H1000 & N565 as they're both extremely stable clean burning options. Then, decided to add in Retumbo & N568 just to see if it might favor a slower burn rate. These are just baseline charge weight ladders below and my notes from each. When I start Load Development on "new" rifles I favor coarse testing right away. I will pick the bullet I want to shoot and a couple powders to run up to pressure before any fine testing. I'll aim at the same point at 100 yards, shoot 1-2 rounds, mark them and repeat while never letting the barrel get hot. This achieves a few things for me on new combinations. Firstly: safe charge weight windows to work with. Second: overall grouping, and also noting if certain charges land together. Generally speaking that can be an accuracy node. By comparing overall groupings of different powders and looking for accuracy nodes it tells me what powder is most likely going to group best with said bullet. Kinda quick & dirty but I've had high success doing it this way without wasting time and components!
H1000
75 - 2964.6
76 - 3012.2
77 - 3055.9
78 - 3083.4
79 - 3135.3 - Ejector mark
80 - Discontinued
Notes: Good group overall with charge weights 76-79 gr clustered together.
N565
75 - 2964.5
76 - 2996.0
77 - 3043.0
78 - 3082.4
79 - 3123.2 - light Ejector mark
80 - Discontinued
Notes: Ok grouping, not quite as clustered up like H1000 but charges 75-76 bunched together then also 78-79 again.
Retumbo
76 - 2963.7
77 - 3021.8
78 - 3057.9
79 - 3099.9
80 - 3135.0
81 - 3169.8 - light Ejector mark
Notes: Good grouping overall with charges 78-81 all clustered up together. Best velocities before pressure of all powders tested.
N568
77 - 2890.0
78 - 2947.4
79 - 2978.4
80 - 3019.6
81 - 3037.1
82 - 3070.3
83 - 3123.4 - light Ejector mark
Notes: Ok grouping with charge weights 80-83 all nearly touching in one cluster. Best case fill of all powders tested.
Based on the testing so far, I'm going to do some group testing with Retumbo and maybe H1000 or N565 with the goal in mind of getting close to 3100 fps with 180's
. Every powder tested is showing really good potential in the 3000-3100 fps range!
Will this concrete display of will-power eventually cave in to the performance and precision that likely awaits?
Be careful doing too much testing, you might fire many more shots that way than with the
choice! 
Should I do an 1.25" straight on the 300 Mega for more opportunity to chop and re-chamber
?
Be careful doing too much testing, you might fire many more shots that way than with the
choice! Should I do an 1.25" straight on the 300 Mega for more opportunity to chop and re-chamber
?
KH_Outdoors
Well-Known Member
Will this concrete display of will-power eventually cave in to the performance and precision that likely awaits?
Be careful doing too much testing, you might fire many more shots that way than with the
Should I do an 1.25" straight on the 300 Mega for more opportunity to chop and re-chamber
You're not wrong!! We'll see what this barrel wants. I do think I'd try some N570 under the 190's though if I get to that point
I'm trying to get there myself with the 7 Mega, the 190LRHT.
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Building one now with a 20" 8 tw. should be a nice little 180 flipper
KH_Outdoors
Well-Known Member
I'm certain it will be! I'll get an update posted here shortly, this cartridge loves nearly everything so far!
KH_Outdoors
Well-Known Member
Update on Load Development:
Thus far the 7-300 PRC project has gone so smoothly and it really has not been a picky one to load for. Most of the testing so far has been with the 180 Hybrids and I ran some quick ladders to find pressures. The main standouts though have been N565 & H1000 in that order. Followed closely by Retumbo too. Here's where I landed with those two powders:
H1000
76.5 gr @ 3070-3080 fps
N565
77 gr @3070-3080 fps
There is definitely an accuracy window in that 3070-3090 fps window on my 24" barrel with 180's. I can push it harder over 3100 but the accuracy isn't there, and the pressure is. Not too shabby!
Next up I'll try the 180 ELDM's, this freebore works well for the 180 Bergers... however it is definitely optimal for the 180 ELDM's & 195 EOL's (considering neck engagement).
Thus far the 7-300 PRC project has gone so smoothly and it really has not been a picky one to load for. Most of the testing so far has been with the 180 Hybrids and I ran some quick ladders to find pressures. The main standouts though have been N565 & H1000 in that order. Followed closely by Retumbo too. Here's where I landed with those two powders:
H1000
76.5 gr @ 3070-3080 fps
N565
77 gr @3070-3080 fps
There is definitely an accuracy window in that 3070-3090 fps window on my 24" barrel with 180's. I can push it harder over 3100 but the accuracy isn't there, and the pressure is. Not too shabby!
Next up I'll try the 180 ELDM's, this freebore works well for the 180 Bergers... however it is definitely optimal for the 180 ELDM's & 195 EOL's (considering neck engagement).
KH_Outdoors
Well-Known Member
My N565 load for reference, crazy good spreads!
KH_Outdoors
Well-Known Member
Load Dev Update!
Decided to try 180 ELDM's & 195 EOL's just because.. of course they shot great! This freebore & chamber is optimal for these projectiles as mentioned before.
Caved and tried the N570 and of course it shot fantastic
180 ELDM'S on average shot approximately 40 fps slower than the 180 Hybrids with the same charge weights of H1000 & N565. N565 is still the leader in accuracy & low ES/SD between the two for me. So coming in Around 3030 fps with the mild powders. Some quick testing showed that it would do really well with N570 around that 3070-3080 fps mark!
195 EOL's shoot great around the 2930-2970 range! Went straight to N570 on this one with the heavies. Great accuracy & low ES/SD but even with N570 I didn't see the Velocities I'd hope for. If I wanted to run 190/195's I'd suggest a 26" barrel.
Next up: the @McGuireBallistics 160 gr CR's!
Decided to try 180 ELDM's & 195 EOL's just because.. of course they shot great! This freebore & chamber is optimal for these projectiles as mentioned before.
Caved and tried the N570 and of course it shot fantastic
180 ELDM'S on average shot approximately 40 fps slower than the 180 Hybrids with the same charge weights of H1000 & N565. N565 is still the leader in accuracy & low ES/SD between the two for me. So coming in Around 3030 fps with the mild powders. Some quick testing showed that it would do really well with N570 around that 3070-3080 fps mark!
195 EOL's shoot great around the 2930-2970 range! Went straight to N570 on this one with the heavies. Great accuracy & low ES/SD but even with N570 I didn't see the Velocities I'd hope for. If I wanted to run 190/195's I'd suggest a 26" barrel.
Next up: the @McGuireBallistics 160 gr CR's!
KH_Outdoors
Well-Known Member
160 McGuires are looking promising.
Looking like the load I'll take hunting this fall.
Looking like the load I'll take hunting this fall.
Ghostface77k
New Member
KH_Outdoors
Well-Known Member
Scrubbed the barrel, fouled back in, and double triple checked. This is the combination I'm planning to hunt with!
7-300 PRC
160 CR @McGuireBallistics
79 gr N565
3180 fps
Checked zero as well as the Single-Feed/Magazine Sensitive model against the Mag-Feed model for POI. All rounds shot from the Magazine to inspect for tip damage. Pic below.
Call that good
7-300 PRC
160 CR @McGuireBallistics
79 gr N565
3180 fps
Checked zero as well as the Single-Feed/Magazine Sensitive model against the Mag-Feed model for POI. All rounds shot from the Magazine to inspect for tip damage. Pic below.
Call that good
Ghostface77k
New Member
Pretty awesome to see how well we got these guns shooting with our official loads with identical components coming in 1 grain apart. Now it's time for a few dirt napsScrubbed the barrel, fouled back in, and double triple checked. This is the combination I'm planning to hunt with!
7-300 PRC
160 CR @McGuireBallistics
79 gr N565
3180 fps
Checked zero as well as the Single-Feed/Magazine Sensitive model against the Mag-Feed model for POI. All rounds shot from the Magazine to inspect for tip damage. Pic below.
Call that good
View attachment 698331
