Gunsmithing Obermeyer

[nuclabuyer]

I have read that a lot of the Obermeyer barrels have a tighter bore then most any other barrels manufacturer. Does this have any effect on the velocity of the bullet and does it cause any higher pressure when doing load development? Looking at rebarreling a 338 edge because I am not getting the accuracy I want from the Montana Rifleman barrel. Bugholes has a few 338 barrels in stock but the one that is closest to what is the Obermeyer. I would rather have a Krieger but I am confident that every barrel manufacturer that he has in stock is as good the Kriegers.

Thanks

 

[JJones75]

Re: Obermeyer

The barrel is only gonna be as tight as its cut , a .300"/.308" isin't gonna be tighter than any other from Kreiger , hart , Rock or whatever

If Boot's cuts his barrels .299"/.307" then itll be a little tighter but nealry everybody makes a "tight bore" 30 cal barrel , it should be listed as tight bore

Ive never seen a tight 338 barrel , though i have very very limited expericant with 338.

either way wou cant go wrong with an Obermeyer barrel

 

[9H_Cracka]

Re: Obermeyer

Go look at Krieger's site. They cut bore and groove dimensions in half a thou increments at the buyer's request. Look over the in stock 30 cal barrels - it will become obvious they do this.

No guesswork or supposition required.

My Krieger 30 cals are .298/.3065 BTW.

 

[nuclabuyer]

Re: Obermeyer

I have seen a couple different people and smiths say that obermeyers are tighter then average. More then anything I am looking for whether a tight bore affects velocity and pressure. I read a post from Chad that says all the Obermeyer's he has chambered were tight, but that they all shoot. Not trying to debate barrel manufactures as much, I want to know if tight bore has any effects on velocity and pressure.

 

[danpd]

Re: Obermeyer

Have a read of this, it may answer some questions, or not.....

Pressure Trials

 

[buffybuster]

Re: Obermeyer

A tight bore barrel usually gives a bit higher velocity (for a given charge) than a standard bore, at the expense of higher chamber pressures. There is no free lunch.

My understanding that tight bore barrels were developed because some Palma events required the use of Radway Green ammo, which had undersized bullets. The tight bore barrel was a better match to those bullets and gave better accuracy. Once tight bore barrels started to win, then "tight bore" became the hot ticket, regardless of the actually necessity. I suppose if you're intended bullet tends to run on a undersized side, then a tight bore barrel might be worthwhile. Otherwise it's just for the fact that you can say "Mine's a tight bore".

 

[Bugholes]

Re: Obermeyer

Something to consider here is that the 5R rifling profile is for lack of better terms, a "trapezoid". The top of the trapezoid would be the tighter bore section, which is the thinnest part of the shape. I have not seen the Obermeyers to have any higher pressure or to be faster for that matter. Boots believes that the deeper rifling promotes longer barrel life- I can't speak about his because I have been working too much to shoot out barrels, not to mention get a little bored and change them out for the hell of it
I have little experience with his 338s, but all the other barrels have been outstanding. I wouldn't avoid it because it's considered a tight bore, but be aware of the tooling requirements before going ahead with one of his barrels

 

[wburke2010]

Re: Obermeyer

Frank Green posted something in the bolt rifle forum the other day comparing two different barrels the other day, I would check that out and see what he had to say.

Walter

 

[JJones75]

Re: Obermeyer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bugholes</div><div class="ubbcode-body">Something to consider here is that the 5R rifling profile is for lack of better terms, a "trapezoid". The top of the trapezoid would be the tighter bore section, which is the thinnest part of the shape. I have not seen the Obermeyers to have any higher pressure or to be faster for that matter. Boots believes that the deeper rifling promotes longer barrel life- I can't speak about his because I have been working too much to shoot out barrels, not to mention get a little bored and change them out for the hell of it
I have little experience with his 338s, but all the other barrels have been outstanding. I wouldn't avoid it because it's considered a tight bore, <span style="font-size: 14pt"><span style="color: #CC0000"><span style="font-weight: bold">but be aware of the tooling requirements before going ahead with one of his barrels </span></span></span></div></div>

Are they made from differant material than typical SS barrels? (416)
I know the old BlackStarr barrles were 17-4 and that the lothar Walther are differant material

 

[baypoint]

Re: Obermeyer

No not different material. You will need a smaller pilot for your reamer so you don't have a sloppy chamber cut..

 

[STR]

Re: Obermeyer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: baypoint</div><div class="ubbcode-body">No not different material. You will need a smaller pilot for your reamer so you don't have a sloppy chamber cut.. </div></div>

This is the key.

 

[Bugholes]

Re: Obermeyer

The throats in chambers cut in these these barrels will be shorter than a traditional bore size, expect to engage the rifling at a shorter COAL. Not tremendously shorter, but a measurable difference

 

[JJones75]

Re: Obermeyer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bugholes</div><div class="ubbcode-body">The throats in chambers cut in these these barrels will be shorter than a traditional bore size, expect to engage the rifling at a shorter COAL. Not tremendously shorter, but a measurable difference </div></div>

Ah gotcha , I figured that the piglet would need to be fitted to the bore

 

[nuclabuyer]

Re: Obermeyer

Perfect, that is what I was looking for.

Thanks

 

[9H_Cracka]

Re: Obermeyer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JJones75</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bugholes</div><div class="ubbcode-body">The throats in chambers cut in these these barrels will be shorter than a traditional bore size, expect to engage the rifling at a shorter COAL. Not tremendously shorter, but a measurable difference </div></div>

Ah gotcha , I figured that the piglet would need to be fitted to the bore </div></div>

Not if your reamer blueprint is specific to the bore and groove diameter of the barrel it isn't, the way my reamers are spec'd.

The point is valid though - understand that ALL reamer blueprints are specific to specific bore and groove diameters. Using it in a different dimension barrel will produce different results.