Discard cold bore shot?

wvfarrier · Jul 13, 2025

I did a search but came up empty.

When you are shooting to test load development, do you discard your cold bore shot?

I ask this because I have noticed that my proof CF 308 barrel has a tendency to send the first shot almost 2" up and left from the rest of the shots. It is so consistant that I can use Kentucky Windage to correct for it most of the time.

Yesterday I tested some 155 TMKs and some 195 TMKs using Varget and BLC(2). I ran the 155s first and got some incredible groups and perhaps the best SD of my life....5! The lowest and highest charge weights shot the best, .301 and .515 respectively. However, on that first shot I did not think to correct for the cold shot and it was a full 2" high and left.

After finishing that string I let the rifle cool for an hour and repeated with the 195s but did compensate for the difference. Boom, it landed dead into the bullseye.

In the future I may just fire a plinking round to settle everything in before proceeding.

Gunfighter14e2 · Jul 13, 2025

When switching powders, w/o cleaning yes.

rustyinbend · Jul 13, 2025

I always ignore my first three shots when I'm doing load development. They're just for sight-in and barrel warming.

Maurygold · Jul 13, 2025

Yes on cold bore. Also first 3-5 after a cleaning

slodsm · Jul 13, 2025

I always load 5 extra of my lowest charge during load development. I don’t bother recording speed or looking for groups on those first 5. They are my throw aways so the remainder will be more consistent with what that charge/seating depth/whatever will perform like.

Simonsza1 · Jul 13, 2025

2” is a crazy big cold bore shift in my opinion. Don’t know if I’ve ever had a rifle with more then a 1/2” max and that was with a suppressor. Guess thot’s why we test it. If it’s a hunting rifle I would work to change that whether it’s a new barrel, tuning etc.

diggler1833 · Jul 13, 2025

It really depends on my barrel. I have a few factory barrels that have a cold bore shift, but it is usually about .1 - .2 mils, and not two inches. Sometimes I have a slower/faster first round on a 'generally cleaned' barrel, but no difference on POI at 100 yards (we're talking 20-30 FPS).

Almost all - if not all - my cut rifled barrels have no noticeable shift (sample size of eight currently). Once I know that no shift exists at 100 yards, I almost never factor a cold bore into load development again...the exception being the velocity of that first round on a CLEAN and cold barrel.

When I thoroughly clean all the way back to bare metal, it has taken a couple rounds to straighten out (1-3 usually).

*But on a fouled cold bore, I'm not seeing any shift. If you've ever been unfortunate enough to watch my rambling and shooting at 650 yards, the first round is always a cold bore. And it has never been the determining factor in my poor performance (that would be me).

At this point OP, I'd be a tad suspicious of either your barrel's stress relief, or how it sits in your stock/chassis.

Simonsza1 · Jul 13, 2025

st1650 · Jul 13, 2025

One of my barrel threw a very bad cold bore shot every time and it got fixed by using a different muzzle device.

straightshooter1 · Jul 13, 2025

wvfarrier said:
I did a search but came up empty.

When you are shooting to test load development, do you discard your cold bore shot?

I ask this because I have noticed that my proof CF 308 barrel has a tendency to send the first shot almost 2" up and left from the rest of the shots. It is so consistant that I can use Kentucky Windage to correct for it most of the time.

Yesterday I tested some 155 TMKs and some 195 TMKs using Varget and BLC(2). I ran the 155s first and got some incredible groups and perhaps the best SD of my life....5! The lowest and highest charge weights shot the best, .301 and .515 respectively. However, on that first shot I did not think to correct for the cold shot and it was a full 2" high and left.

After finishing that string I let the rifle cool for an hour and repeated with the 195s but did compensate for the difference. Boom, it landed dead into the bullseye.

In the future I may just fire a plinking round to settle everything in before proceeding.

For target shooting, yes. . . I always shoot a couple "cold bore sots" before load development, especially after a cleaning.

For a hunting gun, where you want your first shot to be predictable, no! In fact, I want to only doe my load development shots when the bore is cold.

wvfarrier · Jul 13, 2025

I have been on a rampage with 308 Win lately.

195 Sierra TMK
Big Horn Origin with 20" barrel
Varget (hot)
CCI #450 Small Rifle Primers
Starline Small Rifle Primer
Annealed
Several of these loads shot amazingly well but all were compressed and well over book max.

#1- Averaged 2605fps and .30" 5 shot group (No pressure)

#2- Averaged 2614fps and .65" 5 shot group (No Pressure)

#3- Averaged 2627fps and .88" 5 shot group (Very faint ejector mark)

#4- Averaged 2635fps and .55" 5 shot group (Again faint ejector mark)

#5- Averaged 2644fps and .23" 5 shot group (Ejector mark and at the very top of the bolt lift it was mildly sticky).

I quit at group number 5 and will not repeat that loading. It still puts this loads well into/equal too 30-06 loads.

According to strelok, load #1 is:
3.3" low at 300 @ 2286fps with
2263 ftlbs
7.7" low at 400 @ 2106fps with
1921 ftlbs
11" low at 500 @ 1911fps with
1716 ftlbs

st1650 · Jul 13, 2025

wvfarrier said:
I have been on a rampage with 308 Win lately.

195 Sierra TMK
Big Horn Origin with 20" barrel
Varget (hot)
CCI #450 Small Rifle Primers
Starline Small Rifle Primer
Annealed
Several of these loads shot amazingly well but all were compressed and well over book max.

#1- Averaged 2605fps and .30" 5 shot group (No pressure)

#2- Averaged 2614fps and .65" 5 shot group (No Pressure)

#3- Averaged 2627fps and .88" 5 shot group (Very faint ejector mark)

#4- Averaged 2635fps and .55" 5 shot group (Again faint ejector mark)

#5- Averaged 2644fps and .23" 5 shot group (Ejector mark and at the very top of the bolt lift it was mildly sticky).

I quit at group number 5 and will not repeat that loading. It still puts this loads well into/equal too 30-06 loads.

According to strelok, load #1 is:
3.3" low at 300 @ 2286fps with
2263 ftlbs
7.7" low at 400 @ 2106fps with
1921 ftlbs
11" low at 500 @ 1911fps with
1716 ftlbs

What’s your coal with the 195 tmk ?

Mike278th · Jul 13, 2025

I have confirmed by chronograph that my first shot after a thorough cleaning is WAY down on velocity. Add barrel harmonics into that and I could see some outliers from the first couple of shots. I usually burn up about three foulers before I start counting numbers

wvfarrier · Jul 13, 2025

st1650 said:
What’s your coal with the 195 tmk ?

2.86"
The MDT mags allow a smidge longer but this keeps me just off the lands and these tmks seem to like it.

Mean_Man · Jul 13, 2025

wvfarrier said:
I did a search but came up empty.

When you are shooting to test load development, do you discard your cold bore shot?

I ask this because I have noticed that my proof CF 308 barrel has a tendency to send the first shot almost 2" up and left from the rest of the shots. It is so consistant that I can use Kentucky Windage to correct for it most of the time.

Yesterday I tested some 155 TMKs and some 195 TMKs using Varget and BLC(2). I ran the 155s first and got some incredible groups and perhaps the best SD of my life....5! The lowest and highest charge weights shot the best, .301 and .515 respectively. However, on that first shot I did not think to correct for the cold shot and it was a full 2" high and left.

After finishing that string I let the rifle cool for an hour and repeated with the 195s but did compensate for the difference. Boom, it landed dead into the bullseye.

In the future I may just fire a plinking round to settle everything in before proceeding.

Nope. Speaking for myself, unless I just cleaned the barrel and it’s got no fouling in it really. (I don’t clean to spotless but do use copper fouling remover after each outing.

Except for that first shot after cleaning, everything counts. And I usually fire one just cause after I clean it then put it away. In fact I very seriously care about cold bore shots.

But then my rifle isn’t for just shooting paper or steel.

HerCoStarNTheBeaverPictur · Jul 21, 2025

My rifles are for hunting. That would not be acceptable for me

Aftermath · Jul 21, 2025

HerCoStarNTheBeaverPictur said:
My rifles are for hunting. That would not be acceptable for me

Most of my stuff is for hunting, as well.
I have to further clarify though. I have different impacts depending on clean or fouled and cold. If I have a clean bore, I am probably not going to use that rifle to take a kill shot with beyond 200 yards. I want it to have at least one but I prefer 3-5 rounds down the barrel to make it dirty. Now, properly fouled, I can definitely predict the first round out of the cold but fouled bore.

secondofangle2 · Jul 26, 2025

There is a guy on here @coldboremiracle and his signature line says a quote from his dad “the first shot is worth all the rest”

And in anesthesia and airway management, we always say “your first shot is your best shot”

So I don’t know why we would discard the first shot unless we were paper killers rather than real killers

coldboremiracle · Sunday at 9:01 AM

If you are a hunter, the first shot is more important than the next 3. I would rather spend hours taking half a dozen shots and be able to anticipate the first shot perfectly everytime, for hunting thats more valuable.

Hickswr · Sunday at 9:12 AM

Every barrel has it’s own unique personality and can behave differently depending on the powder type.

My last barrel PRS barrel took 3 shots for speed to leveling when using varget when the rifle was ambient temperature (with a dirty barrel). 2nd shot would be 20 fps faster than the first and the 3rd shot 40 fps faster than the first. Switched to RL 15.5, and the first shot would be the same speed as all the others.

Gunfighter14e2 · Sunday at 9:32 AM

coldboremiracle said:
If you are a hunter, the first shot is more important than the next 3. I would rather spend hours taking half a dozen shots and be able to anticipate the first shot perfectly everytime, for hunting thats more valuable.

And depending on your target, once you pull the trigger you just told everyone/thing in that A/O its game time. One of the reasons the skill set of how to get home w/o leaking, is so important.

nagantguy · Sunday at 9:41 AM

For load development for a target gun sure .
And cold bore shot shift is common but I’d be pissed and suspect of a 2 inch shift .

I only have one dedicated “target rifle” that oddly went on my last elk hunt but as we shoot varmints year around , hunt almost all species that can be hunted in the Great Lakes region and shoot lots of crop damage deer - the cold bore shot IS the money shot .

But after cleaning and or switching loads - he’ll ignore the first half dozen shots until ya figure it and everything settles

supercorndogs · Monday at 8:27 AM

When shooting an ocw test, I usually have some fowlers to shoot before I start the test. As with everything it depends though. I have had a couple barrels over the years that liked to be weird. One took about 20 rounds to foul in after cleaning and did really weird cold bore stuff if it wasn't dry patched out before a trip to the range. Life is to short to deal with shit like that. So to the trash it went.

nagantguy · Monday at 10:47 AM

supercorndogs said:
When shooting an ocw test, I usually have some fowlers to shoot before I start the test. As with everything it depends though. I have had a couple barrels over the years that liked to be weird. One took about 20 rounds to foul in after cleaning and did really weird cold bore stuff if it wasn't dry patched out before a trip to the range. Life is to short to deal with shit like that. So to the trash it went.

Absolutely!
My first “precision” rifle that wasn’t a off the shelf Savage did weird things - it was an early Begara HMR- had the right chamber and the powder coating buildup that prevented the bolts from bottoming out stock to action and did this really weird thing where it would start printing 2 separate groups when it wasnt perfectly shiny clean.
I bought trouble - got it cheap from a guy who said it had potential but he couldn’t get it to be consistent.
Luckily when I sent it back to manufacture I got it back with a new barrel and it’s been lights out ever since . Now I’m glad I bought a used problem rifle cheap. I decided to give them one chance to make it right or it was going on gun broker cheap. Well they fixed it for sure

wind gypsy · Monday at 10:56 AM

I had a carbon barrel that behaved like that, slightly less extreme. It got gone because there's no reason to put up with that shit.

nagantguy · Monday at 11:56 AM

The franken gun an AR 10 gasser that brought me to the Hide to unfuck its unholy malfeasance and malfunctions . It was a fun journey- learned a lot it now runs great - 1 stoppage in the last 610 rounds , but I won’t do it again . If it don’t work I’ll sell or give it away .

supercorndogs · Monday at 12:33 PM

Getting a gun running is one thing. Chasing load development in barrel that has something wrong with it, can cost a new barrel in compoents pretty fast. It can also take fun out of it real quick. Or for some people it is the fun part. Not me. I want to choot.

W54/XM-388 · Monday at 12:52 PM

That whole business is one of the reasons my old AW rifle with the original Border barrel is still the rifle I'll bet everything on.
Clean, dirty, first shot after a couple years, or 10 shots into it, all hitting the same point of aim.

When it isn't just games, chances are you get 1 shot and that's all that counts.

nagantguy · Monday at 1:15 PM

W54/XM-388 said:
That whole business is one of the reasons my old AW rifle with the original Border barrel is still the rifle I'll bet everything on.
Clean, dirty, first shot after a couple years, or 10 shots into it, all hitting the same point of aim.

When it isn't just games, chances are you get 1 shot and that's all that counts.

I can count on one hand the times a dear boar bear elk coyote or whatever has stood still and offered a second or third shot that didn’t involve them running a lt full speed through brush trees boulders or over mountains.

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Discard cold bore shot?

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