Cold bore shot

[bigbrowndog]

If I wanted to test my cold bore shot for repeatability how long would I have to wait between shots to get a true record? days, hours??????????.

Trapr

[JimmyZip]

I am thinking when the barrel has reached a temperature close to what it was before you fired the last shot. At that point tolerances should be the same as the alloys would probably have cooled and returned to their "cold" demensions.

That's what I'm sticking with.

Jimmy

Edited April 20, 2009 by JimmyZip

[bigbrowndog]

yeah but whats close, 2degress, 5 degrees, 10 degrees. And now I have to have an accurate temp gauge??.

I was thinking 1 shot an hour would be OK, maybe even 1 every 1/2 hour. But I am in the dark here, I may have to ask my good buddy, Robbie "Extreme Marksman" Johnson. I'll be seeing him next week, hopefully he'll have my new stock.

Trapr

[JimmyZip]

Make sure to post what he says. I am very curious about this as well. I have a couple of rifles that will get really hot when fired alot. One is my SOCOM 16. That thing gets smoking hot. Reminds me of the MG I carried around in the Army. Also, I have a Winchester Mod70 in 243 WSSM. If you are grouping, you'd better pace them out or that barrel will be hotter than heck.

Sure shoots good though. That thing will shoot 1/2 groups at 100, and doesn't really drop much at all until it gets out to 350. After that and the ballistics do suffer. Sure is a nice little rifle though.

Enough drift, let us know,

Jimmy

[milanuk]

Just shoot your cold bore shot as the first round out for the day. Shoot 1 cold bore, and then a four shot group on a dot nearby so you can see easily how much it varies. Then go about your business, shoot, practice, whatever. Next time you come to the range, do it again. 4-5 times and you should have a good (and pretty realistic) idea of what your first cold shot out of the gun will do - and how you do for that first 'cold brain' shot of the day before you get all mentally warmed up and settled in. If you clean after every outing like some folks do, that will really show you any effects of a cold *clean* bore as well.

YMMV,

Monte

[uscbigdawg]

Trapr,

When testing cold bore, I do a couple of things:

1 - I wait about 5-7 minutes between shots.

2 - I always shoot the cold bore with a fouled barrel, but for analysis, I'll only do test cold bore for like 5-10 rounds before cleaning, fouling and then re-testing. It's the only way I can see getting a fair baseline for comparison.

3 - Like mentioned above, I try to walk away from the bench, doing something else and not think about the shot. It's not just a cold bore, but "cold brain" is pretty accurate too.

Rich

ETA: Good term Monte. I'm stealin' that one.

Edited April 27, 2009 by uscbigdawg

[JKSNIPER]

True cold bore shots should be fired in the condition the rifle is stored in.

I advocate the "Cold ,Clean, and Dry" school of thought since it is the only truly repeatable condition for the rifle.

The moment you shoot the rifle it undergoes slight changes due to the fouling now present in the bore/chamber/etc...

Cold bore training:

Day 1:

Shoot your 1st shot of the day on target #1. THATS your cold bore shot.

Shoot on other targets the rest of your range session.

Clean the rifle (Whatever your regieme is for cleaning) finishing with a "Gun Scrubber" flush of the barrel/chamber.

SAVE YOUR TARGETS.

Use your data book and log all shots.

Day 2:

Shoot your first shot of the day on target #2 (Same type as target #1)

Shoot on other targets/clean /etc...

Keep doing this until you see a pattern emerge in how YOUR rifle performs when in a "cold bore" status.

Usually will take a week or more of this type of shooting.

Also you'll see changes due to temp changes and barometric pressure, and lighting, etc....

Cold bore shot on a sunny summer day at 10 am with temps in the 70-80 degrees and very humid will probably differ somewhat from the shot taken when its overcast, in the 50-60 degree range, and dry as a bone.

You MUST perform this in al types of weather so you know the C.B. for each weather condition you might be facing.

This is why we police sniper types are so freaking boring...we collect data for review and are anal retentive.

We have no life ......(sob!)

Info like this is what helps you to pull out the rifle on an unfamiliar range and look around at the conditions, and figure that I'll......oh put on about 4 clicks of elevation....that should do it....then go shoot high score at the event.

Other guys are still trying to figure out what their rifles going to do for the day and you already know because of all the boring crap you did for months.

Good luck hombre.

JK

Edited April 28, 2009 by JKSNIPER

[Joe4d]

The only shot that really matters in a hunting rifle and I guess in a tactical MOR rifle is the first shot fired from the condition the rifle is usually stored, This is also the true test of acuracy for that style of rifle. Shoot the rifle one shot at a target. Save that target. Each trip to the range next day or next year. Fire a shot at the same target, repeat till you get a 5 shot group.

[bigbrowndog]

Thanks guys I spoke with Robbie this weekend at the BRM3G, and his ideas were pretty much the same as those already mentioned. He said he is more concerned with the CLEAN COLD bore shot than the dirty cold bore shot.

So I'll go the the range and take a target back and forth as well.

Trapr

[Dwight Stearns]

Trapper,

As the other posts advise, the rifle should be at normal room (storage) temperature. When I attended law enforcement sniper school a few years ago, we started each morning with a practice qualification which included a cold bore shot followed by the remaining 9 qualification shots. On qualification day we again started with the cold bore shot. If that shot was on, we were allowed to fire the remaining 9. If the cold bore shot missed, that was considered a failure and we were to put the rifle away but were allowed to retry after a 4 hour wait. I was lucky(?) and didn't have to retry. It did help though that I was shooting the most accurate rifle on the range that week.

I may be superstisious but I will not deploy with a clean rifle. After cleaning I fire one round through it and then put it away. I find that with my rifle there is much less deviation between a fouled cold bore shot and a warm barrel than there is between a clean cold shot and a warm barrel.

Dwight

[RufDog]

If I may....

This whole cold bore fallacy is way overrated & less about temperature than it is about having a fouled barrel. Now if you have a bad bedding job tempurature will be an issue and your groups will walk as things heat up. In a rifle with good parts and fitting I have never seen a true cold bore shot (clean barrel) more than 1 minute out & in my experience it is typically reliable. I personally try to make sure I show up for everything with a fouled bore (to include the deer stand).

[bigbrowndog]

Thank you Rufdog, 1 moa is more than I care to miss when engaging targets beyond 500yds. due to the other affects that the Earth throws at you.

Knowing beyond a shadow of a doubt where that first round out of the rifle will be is what I am trying to find out. Within 1moa is not close enough for my desires right now.

BTW, for those of you always looking for the next best thing, Robbie Johnson is making a TAC rifle stock that weighs less than the AI comparable stock, and uses AR buttstocks and pistol grips, it is bolt on and ready to go in no time, it accepts most all aftermarket triggers ( I say most because he is not sure about the one I want to put in it, yet) It also has an enlarged receptacle for the recoil lug. It really is cool, if you saw the latest Sniper Competition on History channel you saw him shooting it. I'll post pics later today.

Trapr

[uscbigdawg]

...if you saw the latest Sniper Competition on History channel you saw him shooting it. I'll post pics later today.

Hell Trapr I thought he was shooting a JP bolt rifle.

Rich

[RufDog]

Thank you Rufdog, 1 moa is more than I care to miss when engaging targets beyond 500yds. due to the other affects that the Earth throws at you.

Knowing beyond a shadow of a doubt where that first round out of the rifle will be is what I am trying to find out. Within 1moa is not close enough for my desires right now.

BTW, for those of you always looking for the next best thing, Robbie Johnson is making a TAC rifle stock that weighs less than the AI comparable stock, and uses AR buttstocks and pistol grips, it is bolt on and ready to go in no time, it accepts most all aftermarket triggers ( I say most because he is not sure about the one I want to put in it, yet) It also has an enlarged receptacle for the recoil lug. It really is cool, if you saw the latest Sniper Competition on History channel you saw him shooting it. I'll post pics later today.

Trapr

I think your best bet is to shoot your gun in 3 rd increments clean on a new target for each group. You can put 1' pasters or whatever you like on a board @ 100 and shoot groups till you see them tighten up and "settle in". This is likely to be in 10-20 rds but some barrels may take more. Once you figure out your sweet spot as far as proper rds of fouling just make sure you have that many rounds through your barrel before you hit the line. You are right, about 1 moa being a lot @ 5 if the tgt is small. As far as literal temperature, find the sweet spot, and shoot a group after it is cooled down. I doubt you see much shift on a good gun hot or cold.