SmallCaliberCentral

Hi All,

Got my first .204 recently and love it! I'm working on fine tuning my reloads (currently 23.0gr RE-10x under 39gr BKs) and picked up the Hornady OAL gauge to work on seating depth. Problem is that either I'm using it wrong, or my rifle has some extreme freebore.

Using the OAL gauge, I get that the max OAL in my rifle is 2.4"! Per the manual, the idea OAL is 0.02" - 0.04" under max OAL, putting me at 2.36" - 2.38". When I seat a bullet to that length, it does not look quite right. It definitely doesn't fit into the magazine, but it does chamber and eject fine. I'm not even sure it would be safe to try - if the case is 1.840" and the BKs are 0.740", and I seat them to 2.38", there's only 0.20" of the bullet actually in the case!

When using the OAL gauge, I set the bullet in until it goes no further. I use the technique described in the instructions where you stick a cleaning rod down the barrel and move the bullet between the gauge and the rod. I don't think I'm seating it too deep - for the life of me I can't feel anything else until it hits that same point. I've tried measuring with both 39gr BKs ad 40gr V-Maxs with the same result.

Has anyone else played around with this tool? Am I using it right? Or is it just my rifle? Is the extreme OAL even safe to try? Is there any known history of Howa 1500s with excessive freebore?

Thanks!
John

Almost all factory .204s have a lot of freebore, you're not experiencing anything new there. It hasn't seemed to hurt the accuracy much, if any, in most of our rifles. Try your rifle and loads, and see if the accuracy is sufficient for your needs. You might be concerned for no reason.

Thanks for the input, Glenn. Good to know it's likely not just my rifle.

Given that, does the .204 respond well to adjusting the OAL at all? I have yet to produce anything spectacular like I've seen on this forum...the current load was the best of a batch working up using the Sierra load data. 23.0gr, while slower, produced a very close second group size at 100 yards (~1"), but the best a 200 yards (4 holes: ~0.8", 5 holes: ~1.5"). I made a string of rounds out to 2.30" OAL, but didn't have a good rest with me that day, I don't think that told me anything.

Thanks!
John

one other thing to keep in mind when using the hornady oal gauge, is that it is meant to be used in conjunction with a comparator. I am also shooting a howa in 204. after doing the oal and comparator thing, i came up with a free bore measurement of .120 to the lands with a 32 gr. v-max. and i have a little over .200 bullet in the case. I am in the process of working up loads for the 39 gr sierra bk's. at this time and have not checked the freebore, but i am using the comparator to measure the length with, and am far enough away so as not to cause myself problems. when i find a load that is reasonably accurate , then i will play with the seating depth, for better accuracy. also a comparator measures the bullet off of the ogive and not the overall length, which will change the distance to or from the lands.

You can, and should, tinker with seating depths a little, but most of our rifles seem to do well with something between 2.25-2.26" range, similar to factory loads. Your rifle may do well at some other depth, and it pays to check that out, too, but I think most guys are pretty close to factory specs, or magazine length. As for myself, I just seat the bullets as far out as the magazine allows, and go with it.

I agree 100% with glenn that you should tinker with seating depths. But, don't let anyone (including me) tell you where to start or what might work. In MY experience, my Savage and my neighbour's CZ 527 both like 2.285 OAL. It's just a fluke that they happen to like the same seating depth though (Well, I havn't quite settled on 2.285 yet). What I do is first find a load that shoots good with 2.260, then play with primers and seating depth. Below is a target I shot today playing with different seating depths. Here is the rundown (All lenghts are overall).

2.260 = 0.503"
2.280 = 0.438"
2.285 = 0.267" +++
2.290 = 0.569"
2.300 = 0.507"

These are in 0.005 increments. Now what I will do (tonights job) is load up some with 0.001 increments. My target tomorrow wil be five three shot groups as follows: 2.283, 2.284, 2.285, 2.286, 2.287. Then I'll see where the very "sweet spot" is. What myself and a friend have found, (as this target shows) is that you get flyers outside of the node. You'll notice that 2.290 and 2.300 have two shots almost in the same hole with one flyer. I've tried five shot groups and have found the same thing. What I have found is that trying to reach out to the lands (more on this in a second) you get so little bullet captured in the case mouth that concentricity suffers. It looks to me like 2.285 is far enough out that it's not a huge jump to the lands, but short enough to consistently produce accurate loads with minimal runout.

I think that having the bullet enter the rifling straight is hugely dependent upon the lenght of jump. Notice how group #2 (2.280, top tight) has horizontal stringing, and group #4 (2.290, middle right) has vertical stringing. Notice how group #3 (2.285, which actually ended up in target #1, then I adjusted my sight) has a little bit of vertical. I am going to say that I need to be a little bit less than 2.285, more like 2.284 or 2.283. This will (acording to the patern) change the node to create more horizontal, or less vertical (and therefor a smaller group).

A cheap trick to try when trying to find your lands (without a nice seating depth tool like John has), is to either create carbon on the bullet of a dummy round with a lighter, or colouring it with a black Sharpie marker then chambering it. When you see a ring on your bullet at the ogive you know you're touching the lands.

Just for fun (while I'm posting pictures), I uploaded a target I shot (five shots) over the weekend with a buddies bench gun. It is a Kelbly's Panda action bedded into a McMillan BR stock with a Jewell trigger. The barrel is made here in Canada by Ted Gaillard and is chambered in 20-220 Russian, shooting 40gr .204 boat tail Bergers!

Here is an update on my seating depth test. What I did was set up my seater to give approx 2.285 overall length. The overall length will vary but base to ogive is consistant using my seater. Then I loaded three rounds and labeled them "0". Then I adjusted the mic on my Wilson seater +1, +2, -1, -2, thousands off from my 2.285, and loaded three rounds of each.
It turns out that 2.285 is definitely the "sweet spot" with this bullet in my chamber. After I shot the test target I loaded up five more rounds of 2.285 and shot a five shot group. This group is tighter because the wind was a little more cooperative.

Wow...thanks for the great info! I think where I went wrong when trying different OALs is that I was also testing different powder weights...4 strings of 5 shots each at different powder weights at 2.29" and another 4 strings of 5 shots each using the same powder weights as the first strings, but at 2.30". To top it all off, I don't think I got anything good from that range day as I was stuck with a crappy rest and was pulling a number of shots.

Can anyone comment on how doing the experiment heikki02003 outlined would effect the pressure? It seems like the ideal way to tweak the OAL is to start with a load that works well and go from there. Would there be any concerns with the pressure rising to an unsafe level within the 0.05" of the test window?

Looks like I've got some more loads to test! Thanks!
John

When you’re load developing, only change one variable at a time. If you change two things, like seating depth and charge weight, you will never know which change caused the resulting effect. I like to start with the recommended seating depth of 2.255 and try increasing charge weight in .2 gr. Increments all the way from minimum to maximum. Then when I find a charge weight that produces the tightest group then I decrease the seating depth in .5” increments. I’ll take that all the way out to .010 off the lands. (if you can on your rifle) Now I know what seating depth works best with this particular load. By the way, never load to just touching the lands, either .010 off the lands or .010 into the lands. You wouldn’t want some to touch the lands and others to be just shy or just into the lands. That would cause varying pressures.

As far as trying to keep the bullet straight during the jump to the lands, that is affected a lot by your freebore diameter. On my XR 100 the diameter is very generous and allows a lot of room for the bullet to yaw. On my custom Panda action Lilja barrel the freebore is exactly .2045 which doesn’t allow much room to roam. Besides I can jam my bullets into the lands by .015 to keep the business end entering the lands straight. I can help my XR 100 by just sizing half of the neck and then seating my bullets. The unsized portion of the neck will keep the round centered in the chamber. Not perfect, but it does help.

I did a seating depth test a long time ago with my XR 100. I loaded five shots each from the recommended seating depth all the way out to the lands in .5” increments and hit the range. I found that 2.255 produced groups as good as any other depth in that rifle. It also allowed me to have more of the bullet seated in the neck resulting in less run out.
After you settle on a seating depth and charge weight you might want to try varying your neck tension. I found that a little more neck tension helped reduce my extreme spread and controlling vertical on the target.

Controlling run out will help eliminate those pesky fliers. Sorry, for running on at the mouth but, I thought some of my experiments might help you a little.

Hi Skipper,

Thanks for the good thoughts. I kinda knew better than to change 2 things at once...I was probably a little too eager to introduce the local pdogs to my new gun!

Is there any thing to watch out for changing the OAL with a near-max load? Which way will the pressures change as you increase the OAL?

What's involved with setting the neck tension? I've got some basic Redding dies - nothing fancy. Would the neck tension be adjusted by how far the seating die sits in the press?

Thanks!
John

Your chamber pressure isn’t going to change appreciably by varying your seating depth. It would have a big difference if you started crimping or actually reached the lands. Then the pressure would go up due to the fact that the bullet is being held in place longer while the pressure builds behind the bullet.

In order to vary your neck tension you will need a good bushing neck sizing die. Then you can just change to a smaller bushing for more neck tension. Be sure to get several bushings so you can play with the neck tension. I’m currently using a .222 bushing when I size my necks. Regular dies won’t allow you to change the neck tension. Redding makes some of the best dies out there. Forester makes good dies also.

I routinely load my custom Panda with the bullets jammed .015 into the lands. There are no signs of high pressure loading into the lands with some pretty stout loads. I have pushed the 35 gr. Bergers at over 4100 fps. with RE-10X before with no pressure signs. Since then I have found that keeping them right at 3900 fps with either Benchmark or VV N133 will stack one bullet on top of the next. Now, of course, this is with a top of the line 3 groove Lilja barrel. A factory barrel isn’t finished with the same attention to detail as a custom barrel. Your barrel might have a tight spot down the bore.
With any rifle you just have to start low and work your way up slowly. I would suggest you use .2 gr. increments because the pressure can build rapidly in confines of a .204 case. Just watch for signs of pressure as you work your way up. Look at your primers each time you move up to see if there are signs of flattening or piercing or excessive cratering. Watch your bolt for signs that it is getting harder to open. If you have a chronograph watch for signs that you are adding more powder and the velocity isn’t going up. When you move up there should be a corresponding velocity increase. If not the pressure inside the chamber is going up but the bullets aren’t going any faster. All are signs that you’re treading on dangerous ground. Back off some.

You just might find, like I did, that there are certain nodes that produce nice tight groups as you work your way up the ladder. When I was load developing with Benchmark, I noticed that my groups came together every time I increased by about 200 fps. My charge weight increased by .8 gr and the groups would come together again. So then I decided that 3900 fps was better than 4100 for shooting 100yard groups so I stayed with that load. Then I found out what charge weight produced 3900 fps with all my favorite powders and realized that the barrel liked 3900 fps regardless of which powder I was using. It just so happened that Benchmark produced two or three of the best groups I have ever shot.