Cold Bore Groups

How much do you focus on cold bore accuracy?

Being a hunting forum the first then next 2 or so shots seem to be the of utmost importance. If you put a 1” circle at 100 yards can you hit it 3 times with a cold bore. I often get distracted by rifles that will make small groups but that’s almost always after some warming up, scope adjustment etc. is it possible to get the cold bore accuracy out of AR-15’s with so many moving parts. I’ve had Palmetto and DPMS rifles both dial in to 1/2” groups but the first shots could be 2” off.

Something ain't right. I have a PSA that will put the 1st 3 shots in a 3/4" circle. I really don't notice any of my rifles throwing a cold bore shot as long as the barrel is fouled. Do you clean the barrel every time you shoot, or once every couple hundred rounds?

I sight in with a good group. Let it get completely cold and shoot 1. I adjust if needed and let it get cold again. Shoot 1 to confirm and I’m done. If an animal needs more than one shot, things are going to be moving so much I don’t care about a tiny group. It’s not going to matter.

My CTR shoots the first one in the same spot as the 4th, 5th, 8th one.

I've spent a lot of time with Mike Rock of Rock Creek barrels before he retired. I learned a ton on barrel physics. There will always be a different point of aim/impact if you have thoroughly cleaned a barrel, removing all carbon and copper fouling. Depending on your barrel, it may take one or a half dozen or so shots for it to settle in. Cold bore shots are a fact of life after a thorough cleaning. In order for your barrel to shoot at it's optimum performance, it takes copper and carbon fouling to fill in the micro groves inside the barrel. Too much copper/carbon fouling and accuracy starts to suffer. If you're cleaning after every shot or every few shots, you'll be chasing your tail to really see how your rifle really shoots. Just shoot it and see how it shoots. After a thorough cleaning (which doesn't happen all that often) with my custom 6.5 CM, my cold bore shots will be left .5" and high .5". It's very predictable. Usually by the third shot or so I can shoot for group. It will shoot in the mid .3's as long as I do my part. It doesn't get cleaned very often. Usually after a couple few seasons, few hundred rounds or I get the itch to clean it. As soon as my accuracy get's in the .6's or .7's it's time for cleaning, then a few cold bore shots and it's ready to go. If I head to the range my rifle will shoot for group from the first shot.

Lots of great custom and factory barrels out there, each will always be different or how it performs. Sometimes the simplest things can make a rifle a real shooter or a real dud. Bullet type/weight and rifling twist rate can drive a person to drink. I've seen many rifles that hate a given bullet, yet shoots lights out with another bullet. A lot of times it's all about finding the right combinations to match your shooting needs/requirements. There's so much more and variables that go into this. Shoot a half dozen shots or so after cleaning. Try different bullet/ammo combinations to find one that performs. Not every rifle is a tack driver, not every shooter can shoot .5 groups.

It's all that matters to me. Here's a three shot group with the 1st from 100 followed by 2 shots from 200. A 7 year old CTR in .308 with a Leupold VX5-HD, CDS set up, the 200 yard shots were dialed. Hornady Factory ammo. This set up has always performed this way, just like my other two Tikka's.

Why would you clean it before taking a shot that matters? Always foul it after cleaning.

If the rifles are squared away, with fouled barrels, the most common factor I have seen cause a cold bore shot shift is a suppressor. Shot two or three can shift away from number one.

On ARs, I can't explain it, but I have seen shot number one shift from the rest. You hit the bolt release and shoot, and it can shoot different from the following rounds.

Myself and a friend have both tested cold bore shot zero on suppressed rifles. And it has to be the first shot of the day. Even if it's a shot many hours later, it won't be the same as the first shot of the day. My daily carry rifle is a bolt action with suppressor. I check cold bore zero fairly frequently, probably once a month. Fire a shot, make note of where it landed, and then do it again the next day. If I've got consistency, I will zero the scope to the cold bore shot POI. I had another rifle that would drop shots two and three .4 Mil low. But it would do it every time. On the single animal shot, that's not a problem. If I've got to make more than one shot (multiple animals) that shift needs to be accounted for. Especially at home, I've got 500 yards line of sight from house and shop. That .4 Mil shift definitely begins to matter.

It sounds as if you're stating that a cold bore shot is the first shot after cleaning and shooting through a barrel that has zero fouling. What you state is true, but not relevant to how the OP has posed the thread.

As it relates to hunting, the cold bore shot is all that matters, IMO. I have 1" dots that I shoot at every trip, all seasons. If I didn't hit it the first shot every time something would need attention.

Yep, even with the suppressor they go in the same spot.



Both my RRA AR's will throw one shot in five; it's got to be the first shot. Is it the suppressor or something else? Don't know, but they still group just fine.

6.8 throws one high:




.223 Wylde throws low:

My RRA varmint rig will 100% throw the first shot about an inch high left, even from a warm barrel. And about 50% of the time it will throw the last round from the mag a little high left. All the other rounds in the mag group bug hole size. I don't see it from any of my higher end bolt guns. Warm or cold, they shoot to the same POI.

I see you still have AR cooties.


QSYB, just interested to know if you are loading only 5 rounds when you shoot these groups? I can't say if I notice a difference in my first shot from an AR like JG experiences but I do seem to see some differences in the last shot of a mag. I think it was Chad that mentioned an empty mag doesn't push up on the bottom of the bolt the same way or with the same force a loaded mag which may partially explain this last shot phenomena. As a result, I load an extra round in the mag when I'm working up a load to shoot groups and just eject the last round and let the rifle cool before shooting my next group.

From what I have read and seen with my own AR, a shot from one that was fed by putting in the mag and releasing the bolt will often have a different POI than the rest from that mag.

@BigFitz, I think both those groups were with full mags. Next time I get a chance to shoot them at the range I'll do the test again and see if they're still throwing, and if so, which shot it is (1st or last).

At the end of the day, all rifles and barrels shoot differently. If you spend the time shooting your rifle, making notes and/or a having a log book, then you'll begin to understand the characteristics of your rifle. You'll know how many shots it will take if you do a thorough cleaning to settle in and shoot well. You'll know what your cold bore shots should be. I'll come back to this again, not every rifle is a .5" or better shooter. Not all shooters have the skills/training to shoot .5" or better groups. Places like JG's and others out there can teach shooters those skills. I'm sure he has plenty of stories where after a day of training. Shooters who couldn't shoot when they got there, started to get it after a few hundred rounds of good coaching. I've had folks shoot my 6.5 CM and barely shoot a 1.5" group. Learning your rifle is very important.

I don't doubt that...guessing the dynamics are slightly different with a bolt released vs. a bolt cycling after fired. I guess I'll need to pay more attention to that first shot and see what I learn.

Last round in the magazine of an AR will impact low.

The bolt locks open and I believe it robs gas. Seen it many times. Spotting for someone, round splash low, they ask if they should dial up more. Nope, bolt locked open. Reload the rifle, keep the same scope correction. Next shot hits the steel.

Watch for it. Slow down. Shoot one, make a note of where it landed, then shoot another one.

"Suppressor pop" is a theory. I think it has some merit. First shot through a suppressor having ambient air in it can change POI from the following shots, that have less oxidizer in the suppressor.

Agree with 1st round 'pop' being a thing.

I shoot a 22 with a silencer on it everyday and have found the fist round pop to be noticeable one day and not the next, No variables changed with the hardware. Just the day.

The weather changed.
The ammo isn't super consistent.
Several things can cause it.

Pop = humidity

At least in my opinion.

With a rifle and no suppressor I think moisture in the barrel is a factor. Try a dry patch through your barrel before the next cold bore and see what happens. I don’t mean clean it. Dry patch only.

I mean this just doesn't make any sense. Robs gas?

I don’t know about it robbing gas because the bullet may have left the muzzle by then, but I do know the bolt locking back changes the recoil impulse possibility effecting poa.

I don't know how prevalent this is, I've never noticed it. The bullet would be long gone, you're right. So, would that not also hold true for the recoil impulse you mention? The absence of a round in the mag may put the bolt in a different position.

I've shot many AR's that were spot on with every shot. I've had some that had first round POI shift, and some with a POI shift on bolt round lock back. The last round, bolt back, lock open is a common POI shift with some AR's. If shooting a 5 shot group, I will load up 6 rounds in the mag. the first round loaded is my dedicated last round for chambering. It gets beat up. But I'll load that dedicated round first, then my 5 rounds to shoot for group. I don't want that fifth round to lock the bolt open and have a POI shift. I'm trying to eliminate variables that cause POI shifts that can effect the POI of that round, and open up the group.

I've talked to some shooters where they will want to shoot a 3 shot group out of an AR. They load up 3 rounds in a mag, and shoot 3 rounds, and the bolt lock back on the third shot. If your AR has a slight POI shift on the first round, and the second round goes where it's supposed to, and the third round causes a POI shift, you will not be getting a tight group. You need to know if that first round causes a POI shift of not. And I'll eliminate that first round out of the group, if I see this, or include it with a notation. When testing for groups, I NEVER let the last round lock the bolt back. I contribute this to the change in recoil impulse. Also, when shooting an AR, you have to "drive" the rifle more and have better fundamentals.

Out off all the atmospheric conditions, temperature, altitude, barometric pressure, humidity's roll is a non-variable. Having big humidity changes isn't going to move the needle of the ballistic performance of a rifle in any measurable way. What minute changes it may have are lost in the other atmospheric changes, spin drift and wind drift. You just can't measure or correct for it.

So try it.

Try what? One thing I really understand is ballistics and ballistic programs. I've assisted on a few of the top ballistic programs that are out there. If you're chasing humidity as a root cause of POI, that's like trying to rope the wind. There are far too many other variables in play to say it's humidity. It truly is a non-factor. Reach out to Brad Mallard at JBM or Bryan Litz at Applied Ballistics. These are two of the top minds in ballistics. They'll both tell you it's just not a measurable data point that you can correct for.

I’m not referring to shot to shot humidity. I’m talking about moisture in your barrel that is there on the first shot and will remain dry on subsequent shots. It can actually be extreme in some cases if you bring your rifle out of a cooler environment than your shooting in.

My apologies, I miss understood where you were going with this. Yep, depending on the gun, temperature differentials between inside and outside it could change POA/POI.

My apologies, I miss understood where you were going with this. Yep, depending on the gun, temperature differentials between inside and outside it could change POA/POI.