Over All Length

[sagebrush]

Take into consideration I know nothing about reloading. First, how important is the over all length of your finished cartidge to the point of impact? If you believe OAL is important, then how much is too much variance?

It just seems to me there are a lot of variables. Case length, bullet seating and tip variance in soft points and polymer tips.

 

[jryoung]

OAL to me only matters that it will fit in the magazine.

Before that I measure for bullet jump where I always start at .050" since I shoot Barnes and that is their recommendation.

I don't have anything with a crazy long throat, so I never run into issue with OAL....despite shooting Barnes which are typically longer bullets in comparative weights.

 

[Bambistew]

I know just enough about reloading to be dangerous. I'm also really lazy when it comes to being extremely consistent. Close enough is good enough for me.

I don't get worked up over OAL "run out". Most dies seat the bullet off some part of the bullet, not necessarily the tip, so you can measure OAL and get slightly different measurements, yet have consistent loads.

A comparator is a tool used to measure from the head to the ogive on a bullet. It will give you a reference for consistent measurements where it counts. Also it might be a good idea to buy a depth gauge if you don't have one so you know what your actual seating depth maximum can be. Some rifles/bullets will be limited by the magazine box...

 

[belly-deep]

Take into consideration I know nothing about reloading. First, how important is the over all length of your finished cartidge to the point of impact? If you believe OAL is important, then how much is too much variance?

It just seems to me there are a lot of variables. Case length, bullet seating and tip variance in soft points and polymer tips.

The effect on POI is nonexistent.

Pressure and feeding are the two biggies associated with OAL. The rule with pressure is: longer OAL increases pressure, shorter OAL decreases it.

It can also impact accuracy.

 

[stillkickin]

The effect on POI is nonexistent.

Pressure and feeding are the two biggies associated with OAL. The rule with pressure is: longer OAL increases pressure, shorter OAL decreases it.

It can also impact accuracy.

Well said, it is amazing how much that bullet seating can change your groups. Especially true with long bullets like the Barnes TTSX.

 

[emrah1028]

As stated, OAL isn't super important to me unless we're talking on the MINIMUM end of things. Seat a bullet too deep and pressures can rise. A lot of the super-precise guys play with OAL by seating the bullet "X" thousands away from the rifling lands. Like .010, .050, touching the rifling, etc.

I don't sweat it too much, as my loads (and most factory stuff) can shoot better than I can. OALs are more of an issue to make sure the rounds fit in a magazine.

Emrah

 

[Redwood]

Bambi touched on it, but to state it bluntly you are actually talking ogive (pronounced with a j). Very generically stated, it is the measurement from the base to the point the bullet contacts the rifling. From there you may have the bullet backed off ever so slightly for "free travel". This is what has a huge impact on accuracy and will be dictated by factors such as the rifle itself and the components with which you use. You will need a tool for this measurement, a comparator such as one offered by hornady. Oal measurements will not work as bullets have different shapes and lengths.

 

[cowboy]

Pressure and feeding are the two biggies associated with OAL. The rule with pressure is: longer OAL increases pressure, shorter OAL decreases it.

It is actually the other way around - that is until you actually start to touch the lands.

 

[sbhooper]

The overall length is most important if you are literally splitting hairs. Some bullets-like Barnes-recommend specific depths due to their length. I usually go by what the reloading manuals recommend or maybe just slightly longer. I have never had a problem getting sub-minute groups from standard bullets using book recommendations.

People that shoot bench rest etc. are the ones that really utilize every small variable when reloading in order to extract the hair-splitting accuracy needed for target shooting. If you desire to play with seating depths, then you can extract better accuracy in some cases, but it is entirely up to you how much you want to play with it.

 

[mtmuley]

I disagree completely. I've had loads demonstrate pretty drastic effects on accuracy with seating depth changes. Certain bullets more than others. I quit measuring from the tip of bullets a long time ago. mtmuley

 

[belly-deep]

It is actually the other way around - that is until you actually start to touch the lands.

No. Roy Weatherby was able to cram more powder into a case without exceeding pressure limits because he freebored his rifles (cut an extremely long throat). In other words, a long gap between the rifling and the bullet decreases pressure and increases velocity (but usually screws accuracy). And so a round with a longer OAL will put the bullet closer to the rifling, thus increasing pressure.

 

[belly-deep]

I disagree completely. I've had loads demonstrate pretty drastic effects on accuracy with seating depth changes. Certain bullets more than others. I quit measuring from the tip of bullets a long time ago. mtmuley

Yep. I've even got the targets to prove it.

 

[jryoung]

I've seen a lot of guys run a ladder test on seating depth alone and the results can be pretty surprising. Thank God thus far the .050 suggestion from Barnes has worked well. In another world where I have more range time I'd poke around with depth a bit more.

 

[sagebrush]

Once you find the sweet spot and measure with a bullet comparator, how much variance will typically achieve the same POI result? Is .001 or .002 inches really that important?

 

[jryoung]

Here's a pick of Breaks Runner experimenting with his 338 Lapua. He was shooting Berger VLDs which tend to be sensitive to depth, but this is a huge difference with just .010 movement

 

[Deleted member 16014]

You want to be measuring base to ogive length, oal is a poor substitute.

 

[huntRme]

I always figured that seating the bullet deeper than the length of the neck would increase pressure (it just seemed logical), so I seat the bullet at the base of the neck and if it doesn't clear the lands I take the rifle down to my gunsmith and he reams out the riflings till it clears + a little more. Only takes a minute. End of problem.

 

[Topgun 30-06]

huntRme---Don't assume anything, especially in reloading! Listen and learn from the posts by mtmuley, belly-deep, and jryoung because they know what they're talking about from both the pressure and accuracy end of reloading.