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Blow Offs


Jon B

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Well this may seem like a stupid question to all you experienced shooters, but, I have been looking at competition entries and they mention blow offs.

 

So go on, what are blow offs?

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blow off s are the first shots of the morning to help with barrel fouling after cleaning and to double check zero etc you usually have blow off shots in to the sand behind the targets when the targets are down

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To expand on Spud's post, most clubs don't allow for them in club matches, so you go straight into the first of your two convertible sighters. It's usually only national league matches and international matches where you see them, maybe a few other major 'Open' F-Class events such as those run in the NRA Imperial meeting.

 

The usual arrangement is for the RO to have the targets up to let people get their rifles set up in line with their target, scopes dialled up to whatever power is to be used. Once everybody on the line is set up and apparently happy, the butts crew drop the targets, and the RO allows the shooters exactly one minute for 'blow-offs' before calling cease-fire. The targets are raised again and 'Message 1' given to start the match.

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PHEW! blow offs :o just got a little giddy there ;)

 

 

I don't know ...... there's always SOMEBODY who'll lower the tone. (And ..... how come it's usually YOU, Gary??) :)

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Cock a snook at all the "must have a clean bore and get all the copper out" brigade if you then only have to foul the barrel before you get your best accuracy for competition again.

Yeah, and also the rules at Bielsy stipulate that a shot can only be fired when there is a target present, so no firing into the empty backstop.....odd as that may seem

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Cock a snook at all the "must have a clean bore and get all the copper out" brigade if you then only have to foul the barrel before you get your best accuracy for competition again.

Maybe hold on that....there is quite a difference between " getting all the copper out' (because copper deposits degrade accuracy incrementally and long term) and 'shoot a fouling shot' (not to copper up again,but to have powder residues that are similar thereafter for your competition shots). Opinions may differ on the efficacy of such practices,but there is a very clear difference between permanent and increasing degradation from copper,and maximising consistent barrel conditions for a string of shots (where permitted,B). Remember too,competition places may be decided by a few thou in group sizes-'best' is a small margin.

Of course these BR guys who shoot 25 shots into an aggregate sub .25 inches at 100/200 yards,or 5shots into sub 4 inches at 1000 yards might be kidding themselves.How do the non-cleaners shape up ?

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A competitive 6PPC benchgun will go 25 rounds - and maybe a few more - before accuracy deteriorates. Few accurate rifles will go more than 45 rounds without showing a deterioration - in my experience.

 

Generally, most 100/200 yard benchrest shooters will clean after a couple of matches - say 15-20 rounds. Some clean after every match - if you go to a 'worlds' cleaning is an obsession, with many competitors cleaning after every match. Most BR shooters subscribe to the 'fouling is the thief of accuracy' adage.

 

Generally, a clean 6PPC gun will shoot to point of aim without any 'blow-off' shots, though most shooters will fire a few 'sighters' if only to 'settle' the rifle in the bags.

 

Lots of 'clean' barrels don't shoot to point of aim until at least couple of 'foulers' are fired. For F Class, this could mean a couple of dropped points - which can never be recovered - so, in my opinion 'blow offs' level the playing field a little.

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I wonder how dirty and copper-fouled the barrel is for the 25th shot.

 

Compare that to the 1st shot after fouling.

 

 

If you want an answer to that, go to a 100 yard BR comp and watch the PPC shooters. They'll usually clean twice in a 5X5-round comp, some more frequently. The patches that appear on the cleaning bench start a nice bright blue.

 

However, that's the PPC at ~3,300-3,400 fps. Anything coppers quick at those velocities and maybe these small-production handmade bullets have rather soft jackets too. It's not at all a copper issue in F-Class and FTR, entirely about getting some powder fouling into the barrel. Many 7mm and .300 F/O rifles produce only marginal copper staining on patches after a whole day's shooting, and a few .308 Win FTR competitors go 200, 300, or more rounds between cleans. Some of these rifles shoot to their normal point of aim with a spotless barrel, many don't. When you're shooting at a target with a 10.5" 5-ring at 1,000 yards and it takes two or three shots for the elevation to 'settle', that's bad news if there are no foulers (blow-offs) allowed.

 

This was one of the major downsides I found shooting 90s in 223 Rem. In two very different rifles with nearly 300 fps MV between them, one thing they had in common was a need for four shots before shots returned to normal elevation - and there was a big difference here, not a tiddly quarter or even half-MOA, in where the first couple went. There was no problem in GB league shoots with the blow-offs allowed, but the two sighters only allowed in club shoots meant a dropped point at least. The only reliable answer was to get a few 'foulers' in before a match so that S1 became a reliable indicator again.

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I wonder how dirty and copper-fouled the barrel is for the 25th shot.

 

Compare that to the 1st shot after fouling.

There are some differences of opinion about cleaning regimes,though most accept cleaning at least helps.....(ask a dentist).

 

Typically,100/200 yard Bench Rest shooters clean their barrels after each 5 shot relay; they start the next relay with a non counting sighter/fouling/wind test shot on the supplementary targets provided for just this.So the barrel is in reasonably similar condition for each string of 5 shots in the group to count. Such BR barrels are exceptionally good,and clean rather easily,way way better than factory barrels. The results seem impressive,so it is unlikely that the cleaning is doing much harm-remember the very small differences between success and 'also ran'-a few thou over 25 shots.

 

There are many who would not be so scrupulous with hunting rifles,-though most do 'clean' regularly-the better the rifle/shooter,the more often-eg after every shooting session-which might be one shot only. 'Varminters' will generally clean after each outing too-maybe 10-20 shots?

Granted,some rifle/shooter/ammo combinations are not good enough to notice the gradual deterioration in un-cleaned rifles-or just don't care.'Mediocre' isn't always bad,its just never good. Their choice,but not the 'Shooter's Choice"---(it's a cleaning fluid).

 

gbal

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I thought its as much about having a few 'free' sighters to check elevations and see what the wind is doing as it is about barrel fouling.

Isn't it a carry over from the muzzle loaders , don't they fire a couple of 'blow offs' using just the percussion cap ?

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Ah, I didn't realise that it was only the bad, mediocre or poor shots that don't clean.

 

I have seen many more barrels' accuracy damaged by poor cleaning than by not cleaning. That is not a reason not to clean, but when you do, get it right.

I didn't actually say that it was only bad,mediocre or poor shots that don't clean-though that may well also be true for many such ,and as Laurie and Vince evidence,very,very few top accuracy shooters-none,in fact-don't clean.I would not be surprised if there were a positive correlation between good cleaning and precision shooting,though allowing that a few field shooters do not clean (much),yet remain competent,probably despite their attitude to cleaning,rather than because of it.No long term study has been done,partly because rifles get changed,almost never because they are shooting too well !

I was trying to be careful and say that some combinations of shooter,rifle and ammo are not good enough to notice a slow decline in accuracy-if your ammo is not capable of any bettter than 3 moa,you shoot a rifle of similar mediocre accuracy-the only one i have had was a Ruger mini 14,but some worn out military ones can be similar,and the shooter shoots offhand,or with poor technique,then there are so many weak links that the deterioration from an uncleaned barrel will be lost in the mix.

There may be shooters who are not very good who clean very well.Are there any who do not clean at all,and whose targets are just as good as they would be if they cleaned? Depends on your criteria for performance-I had a 7mm which was three generations old,probably never cleaned before I had it,yet was a reliable deer rifle,according to it's previous owners (I don't think it shot at many roe beyond 100y),and I could put 3 shots in about 2 -3 inches at 200y..Most cleaned rifles I have shot would at least halve that grouping,and some would be even better,despite having probably shot many more rounds. You might have to shoot at a considerable number of deer to find any difference,though.

 

You are correct about proper technique in cleaning-like anything else that is desirable,it were better to do properly,and poor cleaning-especially wear around the muzzle,can negatively affect accuracy.But you are also correct in concluding that is no reason not to clean well.

A competition barrel in stainless may be somewhat more resistent to corrosion etc,and easier to clean;few are left uncleaned though.Why might that be?

I see no reason to abandon the dental analogy-good cleaning promotes dental health,neglect makes problems more likely.

 

What do you shoot,do you clean,and what results do you get?

gbal

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I shoot mainly competition, GRSB, MR, GRFB, PR (of old), highpower and CSR, but I also hunt everything from rabbits to deer.

With all my straight-pull/bolt guns, they get lubrication as required and a pull through if they are stored for any length of time (most don't sit idle for very long at all). If they get rained on or otherwise dirty they will get a thorough clean.

The competitions usually require the greatest accuracy and reliability at the end of the day where you don't usually have time to clean and after you have already fired anything up to 100 rounds.

I have won many competitions and placed in many more, I have competed both nationally and internationally with good results.

The only firearms that get a thorough cleaning are the semi-autos I shoot but then only when they are starting to get a bit too gritty.

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I shoot mainly competition, GRSB, MR, GRFB, PR (of old), highpower and CSR, but I also hunt everything from rabbits to deer.

With all my straight-pull/bolt guns, they get lubrication as required and a pull through if they are stored for any length of time (most don't sit idle for very long at all). If they get rained on or otherwise dirty they will get a thorough clean.

The competitions usually require the greatest accuracy and reliability at the end of the day where you don't usually have time to clean and after you have already fired anything up to 100 rounds.

I have won many competitions and placed in many more, I have competed both nationally and internationally with good results.

The only firearms that get a thorough cleaning are the semi-autos I shoot but then only when they are starting to get a bit too gritty.

Good stuff and well done.Absolute precision ( ie .4 rather than .5 moa) isn't the most important consideration for a sporting rifle.

 

And presumably in protracted competition success ,the other competitors will have a similar lack of time to clean,so any effects are broadly shared?

 

But it would be interesting to know if you can detect any slight drop off in performance after say 100 rounds.

gbal

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