Help, please - Marlin 795 throws first shot 4-6 MOA off target

[Harmonica]

I've got a 795 that will clean stage 4 if not for the first shot going off target. It does it not only slinged up but also when placed on front and rear bags as well. Any idea what causes this? Heard of it happening in other 795's? Is there any way to fix it or work around it? It'll shoot 2-3 MOA groups off the bags after that first shot and I've got 6 mags for it so I'd hate to give up on it.

[Roswell]

Are you letting the bolt run forward on its own or slowly riding it forward? If you are riding it slowly forward, it may not be seating correctly.

[George63]

or work around it?

the work around would be to put the first one in the mag into the AQT sighter square each time - it would require a mag change on stage 1 and 4


1st round point of impact deviation is a commonly observed phenomenon with semi autos of all types, just not that much

[FiremanBob]

Does this happen only after cleaning the bore, or on the first shot from every mag? If the latter, as Roswell said, try letting the bolt fly forward under spring pressure without riding it when charging that first round.

Please try it and let us know the results.

[misawa]

In addition to the above...

Load 1 round in each mag and do your part.

Do the shots group together?
Do any hit your aimed-at target?

[jmdavis]

Are you sure that it is not one paticular mag that has the problem. Number your mags and then test. 1 shot is not enough to heat up the barrel and on an AQT your barrel is already warm.

[Luminous Rabbit]

This is a common problem with .22s (both bolt and auto).  Once obvious stuff like the first round getting mangled coming out of the mag is ruled out, there is generally one cause.  The problem is that you get a lead ring in the barrel just in front of the throat where the chamber reamer leaves tool marks.  On the first shot, that ring is cold (and thus hard) and swages down the bullet a few thousandths.  As a result the bullet bounces its way down the bore and impacts away from normal point of impact.  The heat from the first shot softens/melts the lead and lets subsequent bullets pass through unmolested, and the effect goes away until you let the barrel cool whereby it comes back.

You can confirm this is the cause by seeing if you fire a second string right after the first whether you get a flier.

If you have this pattern, it can be cured temporarily by cleaning the lead out of the barrel with lead solvent (either liquid or on patches), but it will come back.  After cleaning, using lubed or plated ammo can help.  Changing to bullets that are a bit oversize (e.g. RWS is about .001 larger than the typical .22 bullet) can help but is expensive.  Removing the tool marks by fire lapping the barrel or just cleaning with abrasives works, but makes some people nervous running abrasives down the barrel.  I have a CZ455 that had this problem, and I ended up replacing the barrel.

[jmdavis]

I have yet to see a 22 that couldn't improve its accuracy and be more dependable with the proper, periodic application of a bent .25 caliber bronze brush of about the length of a fired .22lr case being used in a rotational motion to clean the chamber. This should be followed with a dry or wet patch on a pull through.

I clean my pistol chamber before every practice of match. I do not take a brush to the barrel however. Sometime you may have a problem with Wax buildup ahead of the chamber too. In times like these a patch with some Kroil on it followed by some dry patches will go a long way.


In this case I do not think that this issue is the problem for the shooter. 4-6 moa is 1.5 inches at 25m. That's ALOT. The test of labeling all of the mags and then firing them with 1 round and multiple rounds will show something.

[Luminous Rabbit]

I have seen first round fliers due to lead buildup that are bigger than that.

In any case, he has the information.  What he chooses to do with it is up to him.

[Harmonica]

Thanks for the suggestions. I'll keep them all in mind and start with a good cleaning. This rifle could use it.

[jmdavis]

I would not put a brush in the barrel. Only the chamber. The only things my barrels see these days are patches on a pull-through.

[sluggo]

If you ever want to start a lively debate, just raise this question. -How to clean a 22?-

My RIA 10/22 clone shoots very well, clustering RWS ammo into a tight ragged hole at 25m, however often times there will be a lone shot~1" away. i wonder if the "lead ring" might be responsible?- I might try running a couple of patches with autosol polish to smooth out the bore? I read an article once where the gentleman swore by tooth paste for this purpose.

[goodoldfriend]

Here is a chamber brush I made with 3/16 inch brass tube. Mine was some scrap from work but it is available at hobby and craft stores.

The brush is .243 with a cost of $1.97 plus tax.

There are commercial versions available.

On a popular rimfire forum they also talk of a carbon ring that interferes with cases seating properly. The cure is the same, chamber cleaning.

[FiremanBob]

GOF: that's a steel-core brush. I recommend paying the extra dollar for a brass-core brush. The best brands are Dewey and Pro-Shot. Especially for the chamber brush, which often is inserted at an angle into the bore, I don't like steel rod-end tools.

[sluggo]

I found this quite extensive article on 22 cleaning, with some really interesting images
http://www.rrdvegas.com/rimfire-cleaning.html

[goodoldfriend]

Fireman Bob. I will look for one.

I have almost a 90 degree bend in the brush but I can see what you mean.

The nice thing about the brush is that I can easily change it.

Thanks for the advice

[AFTERMATH]

Are you firing in cadence?

[Guntuckian]

I had a Marlin Model 60 that would throw the first round of every string 5-6 MOA off in a random direction.   It had an 18 round magazine.  Was never able to get it to work, despite cleaning the chamber/barrel  to remove the lead ring.  If you dropped cadence, the first shot after waiting about 10 seconds would likewise be another flyer.  If you verified NPOA on stage 4 sillouettes, the first shot on each sillouette would likewise be another flyer.  Yet, if you fired all 18 rounds on a single stage 4 sillouette in cadence, you could put all but the first round in the same sillouette easily.  I sold it off, and never regretted it.  It apparently had a thermal problem in the barrel to receiver junction.  For a casual plinker, satisfied with a 5 to 6 MOA group, it did not matter.  For Appleseed AQT use, it was a disappointment.  Sometimes, it is not the shooter, but is the rifle.  YMMV