Cold fouled bore 1” high

[Orr89rocz]

The only gun i have that i noticed this issue in is my .308. Its a 16 lb gun with a apollo max brake that i try shooting somewhat free recoil on the bench but bipod prone in the field while hunting or shooting steel. Couple hundred rounds thru the barrel after doing some load development for a few bullet types but this so far is using berger 180 elites and powerpro 2000. I’m fairly happy with the group accuracy so far, may try some more fine tuning but besides the point, i got a first round cold bore fouled barrel shot that seems 1” high. Barrel has 30-40 rounds or so since last cleaning and shooting good but that first shot of the day is 1” high and wondering why.

Is it some residual stress in the muzzle brake to barrel connection? In the stock? And before anyone says shooter i really dont think its me cuz i shoot several other rifles without brakes that dont do this, first cold fouled is always right with the group, its not near this different. And i shot this gun last in my rotation at the range so I already was in the groove of shooting so to speak, not like i pulled first shot of the day. Now the groups were shot couple months apart in different conditions and the more open group i might have rushed slightly but the same trend applies. Just curious if this is something i could fix or just nature of the beast

 

[K22]

I will be watching the replies. I agree with you, it isn't you.

I had a Rem Model 7 that did the same thing, a 1/2 moa rifle after the cold bore shot. The first shot would go about 1 to 1 1/2-inch high, same place, ever time. The clean barrel shot was even worst, i.e., higher. After my smith and me tried a number of potential fixes, never solved the problem. Can't hunt with this rifle but it makes a fine range practice rifle after I dump the first round in the bank.

 

[markm87]

Anyone who claims to know this with certainty is full of it. I've heard guys say there's no such thing as cold bore, just cold shooter. No way. We just watch way too many guns/barrels do weird things every week.

 

[Orr89rocz]

I will need to try checking it on paper at longer range like 565 where i shoot steel. I will also try my other 165 tipped game king load to see if it also does the same thing. I do have some 168 smk rounds too that i didnt load for this gun but my dad did and they shoot ok. I dont see how it could be a bullet type thing but gotta rule things out i suppose

 

[K22]

Anyone who claims to know this with certainty is full of it. I've heard guys say there's no such thing as cold bore, just cold shooter. No way. We just watch way too many guns/barrels do weird things every week.

Here's one for you, two rifles, both Model 7's, both with Douglas Match barrels from the same reamer and same smith, both with B&C Medalist stocks, both the Leupold VX3 scopes, both with tailored reloads, both fairly consistent 1/2 moa rifles off the bench. But one tosses the cold barrel shot 1 to 1 1/2 inch high every time, same about the same location.

It's the only rifle is 50 some years of shooting that I've experienced this.

 

[dcali]

Sometimes they just do that. I've' had barrels that would reliably throw off hte first couple, and others that were dead on from the start. I don't think anyone knows exactly why.

 

[ASD9055]

Just asking, could it have anything to do with the fact the the follow up rounds, the cartridge is warmer than the first? Hot chamber, warms up cartride.

 

[barefooter56]

The only gun i have that i noticed this issue in is my .308. Its a 16 lb gun with a apollo max brake that i try shooting somewhat free recoil on the bench but bipod prone in the field while hunting or shooting steel. Couple hundred rounds thru the barrel after doing some load development for a few bullet types but this so far is using berger 180 elites and powerpro 2000. I’m fairly happy with the group accuracy so far, may try some more fine tuning but besides the point, i got a first round cold bore fouled barrel shot that seems 1” high. Barrel has 30-40 rounds or so since last cleaning and shooting good but that first shot of the day is 1” high and wondering why.

Is it some residual stress in the muzzle brake to barrel connection? In the stock? And before anyone says shooter i really dont think its me cuz i shoot several other rifles without brakes that dont do this, first cold fouled is always right with the group, its not near this different. And i shot this gun last in my rotation at the range so I already was in the groove of shooting so to speak, not like i pulled first shot of the day. Now the groups were shot couple months apart in different conditions and the more open group i might have rushed slightly but the same trend applies. Just curious if this is something i could fix or just nature of the beast

If this is occurring at 100 yards its not unusual. The velocity is lower causing this. As you lay more fouling down in a cold fouled barrel it can take a few rounds for the velocity to stabilize again. You can see this in the lower bullet strikes. As the velocity increases at 100 yards the rifle shoots " flatter" due to the increase in velocity. At longer ranges this will be reversed. The cold fouled bore strikes will be lower. As the next rounds are fired the round strikes climb on the target till the velocity is stabilized due to fouling added to the barrel. I experienced this at CAMP PERRY shooting PALMA. I never cleaned the rifle the whole week. And every day on the first relay it took at least 5 sighters till my elevation came back.

 

[chop house]

you mean like this? lol i always thought it was this rifle settling into the bags.

 

[divingin]

I have some experience with this (not saying I know how to fix it.)

I was carrying my break-in routine over to post-break-in (was cleaning as well as possible and following with a degreaser and a final layer of fine graphite to try and minimize copper fouling.) Post break-in was generally cleaning every 25 rounds. First shot after the cleaning (or the first shot of the day) would go 12 o'clock to high right, about 1/2" or so at 100 yds. The times I chronographed showed a velocity 100 to 150 fps slower than every other shot.

In an attempt to figure out why that first shot was off, I changed the routine to eliminate the graphite. That didn't change the velocity drop on the first shot, but it did bring the first shot roughly back into the group.

Bottom line: Don't ask me; got no clue.

 

[Orr89rocz]

Just asking, could it have anything to do with the fact the the follow up rounds, the cartridge is warmer than the first? Hot chamber, warms up cartride.

I dont think. It first time i did this it was cold out and i waited a minute or two before second shot. One shot on a 1” bull doesnt do anything to heat the barrel imo. I understand it can def have an effect but i rarely let the barrel get above warm. I try to keep it roughly same temps for any set of groups im firing, got a chamber cooler running and sometimes cold rag for barrel in summer. Do most of my shooting in 30-50 deg weather to simulate hunting seasons

 

[Orr89rocz]

If this is occurring at 100 yards its not unusual. The velocity is lower causing this. As you lay more fouling down in a cold fouled barrel it can take a few rounds for the velocity to stabilize again. You can see this in the lower bullet strikes. As the velocity increases at 100 yards the rifle shoots " flatter" due to the increase in velocity. At longer ranges this will be reversed. The cold fouled bore strikes will be lower. As the next rounds are fired the round strikes climb on the target till the velocity is stabilized due to fouling added to the barrel. I experienced this at CAMP PERRY shooting PALMA. I never cleaned the rifle the whole week. And every day on the first relay it took at least 5 sighters till my elevation came back.

I’ll have to try through the chronograph but i havent seen that before that the first shot is slower. Not saying it cant be but I haven’t seen that in my other guns. But i got a magnetospeed sporter and its not working well with the long brake on the gun, i usually have to take brake off to get velocity data for this one.

 

[Orr89rocz]

I have some experience with this (not saying I know how to fix it.)

I was carrying my break-in routine over to post-break-in (was cleaning as well as possible and following with a degreaser and a final layer of fine graphite to try and minimize copper fouling.) Post break-in was generally cleaning every 25 rounds. First shot after the cleaning (or the first shot of the day) would go 12 o'clock to high right, about 1/2" or so at 100 yds. The times I chronographed showed a velocity 100 to 150 fps slower than every other shot.

In an attempt to figure out why that first shot was off, I changed the routine to eliminate the graphite. That didn't change the velocity drop on the first shot, but it did bring the first shot roughly back into the group.

Bottom line: Don't ask me; got no clue.

Yeah i never used graphite or anything like that. I usually clean and fire 3-4 foulers of whatever load and then my known load 1-2 of those to recheck zero. This issue is not on a clean bore however, its been fired a good bit. Clean bores first shots i have seen hits way off but i expect that

 

[ASD9055]

I dont think. It first time i did this it was cold out and i waited a minute or two before second shot. One shot on a 1” bull doesnt do anything to heat the barrel imo. I understand it can def have an effect but i rarely let the barrel get above warm. I try to keep it roughly same temps for any set of groups im firing, got a chamber cooler running and sometimes cold rag for barrel in summer. Do most of my shooting in 30-50 deg weather to simulate hunting seasons

I was thinking about the chamber, warming up the poweder, was just a thought...

 

[barefooter56]

you mean like this? lol i always thought it was this rifle settling into the bags. View attachment 1433068

With shooters using a rest this may be the case. I am not a " bag shooter" per se. I shoot prone or use a bipod

 

[barefooter56]

Just asking, could it have anything to do with the fact the the follow up rounds, the cartridge is warmer than the first? Hot chamber, warms up cartride.

That could be an answer also. Test it and let us know!

 

[mikecr]

With this one you'll need to choose: cold bore accuracy, or hot bore precision.
Make your choice and load develop for that

 

[Liven The Dream]

Had a FN Browning in 30.06 Cold and Clean first shot High and Right.
Always went Hunting with a dirty Barrel ?

 

[AlNyhus]

What stock is on it?

 

[Ned Ludd]

Aim 1" low on the first shot. Problem solved.



Trying to understand why it happens may be a bit more difficult. Have you ever measured velocity for that first shot as compared to the others? Clearly velocity changes happen with a clean bore, but may be also occurring be occurring with a fouled, cold bore. A sufficient velocity change could mean a different muzzle launch angle, which can be enough to displace a shot 1" at 100 yd.