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6.5mm creedmoor with 122 gr flatline bullet help / suggstions

zackm

Sergeant
Full Member
Minuteman
Oct 30, 2013
177
7
New Castle, PA
Anyone have any ideas? see below

I just received an order of the flat line bullets to try in my Ruger RPR. Was pretty excited to get them but that was short lived lol. they look outstanding but how they shoot is another. couple of questions about what you did with them when you loaded them. I shot them out of the RPR with a Silencerco hybrid can, I use it direct thread. the brass is Hornady 1x fired and annealed full length sized chamfered and debured. bullets drop in nice and smooth. I tried both CCI-Br2 primers and 210m primers. The powders I went with where the Varget and IMR 4166. I proof tested working up on the 4166 to the load you used (41.5) and it did the same thing popped primers. the next load was 40.9 and it did not pop the primer but still was on the warm side so I ended up loading (5) at 40.3 and (5) at 39.8 the 40.3 was worse then what you would get with 00 buck at 100 yards really not kidding group was over 5" at 100 yards. the 39.8 was a little better in that it was around 2.5" to 3" at 100 yards.
then tried the varget at 43.0, 42.4 and 41.8 all terrible worse then the IMR4166. Really did not know that a 6.5 Creedmoor could shoot that bad lol. when I was done I was in shock thought ok my scope is loose something going on bullet is hitting something on the way down range ect. so I grabbed 2 of my normal rounds 140 gr Berger vld hunting with h4350 and 2 shots center punched under 1/4" so ruled out gun issue and shooter issue for now. all rounds where loaded at COAL of 2.820 and almost touch lands maybe about 0.005 jump.
now that I gave you a little back ground on them I have few questions if you do not mind. I noticed that in Franks review he shot them thru a brake not a can. was there a reason for that do they not like can's?
next dog I'll hunt with is h4350 just to see if I can get them to group or do you think I should try something else?
the groups I got where so bad I doubt a little change is going to bring about a 180 degree change. by little change I mean using any combo of what I already tried or would you try slowing them down some? I did notice like I said the slower rounds (assuming lower powder charge slower bullet) the groups did tighten up by half. Maybe the 24" barrel with a can is really spitting them out faster then Frank did with the 22.75" and no can barrel and they are not stabilizing? I did not chrony any of these I do not like to do that when testing be because I do not like to let vel. influence my decision on what I will use, I like to let the target talk not the vel. just thinking out loud here a little as I type. maybe next I send a couple of them over the chrony and see what it says for vel.? if it is really high maybe that is my issue? thanks for any insight you can offer or suggestions.

 
You have to work up a load, just like with anything you cannot just fall into it. I highly doubt my information will translate to an RPR directly. I am using a Bartlein Barrel.

It can be the gun because solids are more sensitive to rifling profiles. Button Cut and Hammer Forged Barrels specifically have shown this very issue.

I don't see where you mentioned speed only slowing them down ? So I cannot say.
 
It can be the gun because solids are more sensitive to rifling profiles. Button Cut and Hammer Forged Barrels specifically have shown this very issue..

Can you say a little more about this (or point me to a source)? My initial results with the 122 flatlines gave me poor groups, while 140 VLDs give me sub 0.5 MOA groups in the same gun.. I do have a hammer forged barrel. I was going to do some more testing, but I would be interested in hearing more about the issues with solids in hammer forged barrels before spending any more time chasing it.
 
1:8 is mine my vel with h4350 was 2970 no joy with it either. I plan on getting a LRI barrel for it in the next year most likely will be made from a bartlein blank.

I do work my losds up i knew frank said his was prabably at the top of the hot end with the 4166 so i proofed 1 round each starting low and working higher. .5 grains until i saw issues and then went back to no psi issues and loaded 5 each at .6 grains apart for until i have 3 sets of rounds to try. Did this with h4350, 4166 and varget no joy on any of them with the ruger factory barrel.
 
Zackm-Do you mind sharing your enviro data?

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Frank, feel free to post up MV, twist, elev, temp and twist in order to tweak/adjust the assumptions below.

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Temp was 78 degrees temp. Humidity was 60% alt. was 800 feet. Baro. Was 28.75 wind was less than 3 mph straight at me. Thanks for the help and info would be nice to figure this riddle out.
 
Seems to me both Varget and 4166 are too fast on the burn rate scale for the load you're trying to develop. Try H4350 or RL17, etc, or others in that range.

Do you have access to Quickload? Have you viewed Lowlights video review on the powders used during his review of these projectiles? Have you had a chance to communicate with Dan Warner on what powders he recommends with this chamber/bullet combo?

Do you have direct experience with this chambering/powder/bullet you'd like to share?

Thanks in advance if you do
 
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acourvil, your comment regarding the 1.3 stability factor caught my attention. I wanted to briefly share my experience with the Flatline 255.5 .338 projectiles I am using in my stock Savage, button-rifled .338 LM. When doing load development, I could get a very stable load, with SDs in the 5-7 range but they did not group at all as well as my regular Hornady 285s do at short distance. I took them out anyway and got all the way to 1840 yards before the heat of Florida afternoon sun and our time limit at that place came to an end.

At one point, while we were working our way out to a mile, the spotter for our group said that he thought that he saw a keyhole impact (not verified) and that my load must be unstable (the Miller Stability factor shows as 1.32, so marginally stable). I was getting good consistent elevation and impacts, so continued on. Finished the day with the last three impacts making a roughly 14" "group" at 1840 yards. Best shooting out of the bunch of us that day, including the guys shooting custom .375 Cheytacs.

My point is, that even though these Flatline bullets didn't give me the one-hole groups at 100 yds. that I've seen with my Hornady 285s, and the stability factor was midlin', the performance at distance was more than adequate and that is with a less than optimal Savage factory barrel.
 
Do you have access to Quickload? Have you viewed Lowlights video review on the powders used during his review of these projectiles? Have you had a chance to communicate with Dan Warner on what powders he recommends with this chamber/bullet combo?

Do you have direct experience with this chambering/powder/bullet you'd like to share?

Thanks in advance if you do

I don't know Lowlight or Dan Warner. I do load for the 6.5 Creedmoor along with a bunch of other rounds, and have a good understanding of burn rates and what they mean for the real world.
 
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