Advice on 308 handloading

[sofakingwetodded]

Hello,

I was lucky to find a friend which let me use some space for reloading. I started loading for my 308 20in 1:10 semi-auto. I am doing OCW right now.

The question I have is on pressure signs. Unfortunately, I left my data at my friends house and don't have it right now. Basically, I loaded a few different bullets (not sure which ones I going to use yet):

I started with the recommended starting powder weight and loaded 10 rounds for each bullet incrementing the charge by 0.4gr. On most loads, I was shy of the max weight by 0.5-0.9gr. All loads were seated to a 2.850 COAL (mag length making and all were at least .050"+ jump)

When I shot these loads, I was recording the fps. I was looking for consecutive shots with stable speeds and also looking for pressure signs. The thing is that none of the loads showed any pressure signs. (ejection marks, cratered primers, gas leaks, flat primers, etc). The only load which would lock the bolt back was the 185gr bergers.

Am I to assume that the loading manuals are conservative with their estimates? I also used a free internal ballistics program which was telling me that most of these loads are overpressure. I loaded more rounds going past the max loads from the first round. I made sure that that I wasn't compressing the powder on bullet seating. The only load that was not able to go past another 1.1gr was the warner 160s.

Does this make sense? I'm going to be measuring case capacity of my lapua brass once I receive the tool I ordered. Any thoughts?

Thank you

[waveslayer]

Re read the OCW test by Dan Newberry. You're not doing it correctly . You start at max reloading pressures and then do the OCW. Read it carefully.

What bullets are you running?

Sent from my SM-G986U using Tapatalk

[sofakingwetodded]

I'm running the following:
175gr Sierra Match King
160gr Warner flat lines
168gr Cutting Edge
185gr Berger VLD
176gr Hornady A-tip
150gr Lehigh solids

I guess I was doing the Scott Satterlee method

[Donny1]

Tagged

I'm no expert but I like math, not "looking for pressure signs". Of course I do look for that but also compare fps, barrel length, etc to published data.

Am I missing something with this method?

[sofakingwetodded]

Tagged

I'm no expert but I like math, not "looking for pressure signs". Of course I do look for that but also compare fps, barrel length, etc to published data.

Am I missing something with this method?

would you be able to share the math you are referring to?

[divingin]

The question I have is on pressure signs.

Signs that show up (generic - both bolt and semi-auto):

Flattened primers - usually appear first. Not a great sign of pressure, as it can be caused by several things. Inspect the curvature from the primer face to where it contacts the sides of the primer pocket: it loses its radius as it flattens. can be caused by loose pockets, too-short brass, or pressure. If you ever get a primer that appears "chefs hat" shaped when decapped (i.e. the face diameter has expanded to substantially greater than the primer diameter), figure out why that's happening - it's generally not good.

Cratered primers: Not reliable as a pressure sign; more of an indication of a too-large firing pin hole or a too small diameter firing pin where it goes through the hole. Can also happen if the hole is chamfered. Or can be a pressure sign (on top of the aforementioned causes.) Can cause primers to "blank", where the crater gets bad enough that primer fails and the little cratered disk blows out (and gets into the bolt/action and causes all kinds of wonky stuff.)

Ejector/extractor marks on case head: These will show up as raised areas on the case, possibly with "wipe" or "smearing" of the mark from when the bolt turns and shaves off part of the raised imprint. Caused by the head being forced against the breech hard enough to get the brass to flow into unsupported areas (ejector hole, extractor cutout.) Usually a sign of pressure, but can be caused by other things as well (excessive shoulder set-back, primarily.)

Case base swelling: Generally a result of high pressure, will cause difficulty in rechambering the fired brass (both before and after normal sizing, as a normal die won't reach low enough on the case to correct it.) Can also be caused by soft brass.

If you are getting gas leakage, blown primers, or failing brass, you are way into the danger zone.

Bottom line is that there really is no definitive pressure sign. Most can be caused by other factors not related (directly) to high pressure. You can use most of the signs above as indicators (especially if you get them in combo), but be aware of the other causes at the same time.

Am I to assume that the loading manuals are conservative with their estimates?

You should. I do. Published data is lawyered down to the point where the data is reasonably sure to be safe in every firearm out there. I very often work a bit above published max (working up to those loads) with no ill effects.

That said, you should still follow the accepted "start low and work up" regimen, as if you go the other way (start at max and work down) you can pretty easily end up breaking stuff (including you.)

I also used a free internal ballistics program which was telling me that most of these loads are overpressure.

Kind of depends on what program.

I like Gordon's Reloading Tool; sort of a poor man's Quickload. Works well for me. I now generally try to stay away from max loads in an effort to maximize brass and firearm life. GRT uses a Max Allowable Pressure - 15% as warning area; I pretty much now load to those specs (though I'm shooting a bolt gun - for auto's you may need more gas to drive the action.)

Does this make sense? I'm going to be measuring case capacity of my lapua brass once I receive the tool I ordered. Any thoughts?

Not really necessary until you get really consistent at loading ammo (IMO, of course, as are most of my statements.)

To your function problems: Does factory ammo work in your rifle? if it doesn't cycle with factory ammo, you probably won't (safely) correct it with reloads.

If it does work with factory fodder, then slowly working up the charge on your reloads may be in order.

I would, however, suggest loading with a single set of components (powder and bullet) ang get that working before moving to others. Too easy to get confused in results and end up outside of the safe zone (or waste components.) You're not alone in this regard; my shooting buddy does it as well.

Good luck

[sofakingwetodded]

I am using gordon's tool, but it tells me that most of my loads are overpressure or beyond the safe limit; including those loads below max loading manual suggestions. I am using the berger book, hodgdon website and the 11th edition hornady manual. I'll measure the web of the cases to see what they are telling me. I'm using new lapua brass. I'm planning on getting a chamber pressure tool soon.

Signs that show up (generic - both bolt and semi-auto):

Flattened primers - usually appear first. Not a great sign of pressure, as it can be caused by several things. Inspect the curvature from the primer face to where it contacts the sides of the primer pocket: it loses its radius as it flattens. can be caused by loose pockets, too-short brass, or pressure. If you ever get a primer that appears "chefs hat" shaped when decapped (i.e. the face diameter has expanded to substantially greater than the primer diameter), figure out why that's happening - it's generally not good.

Cratered primers: Not reliable as a pressure sign; more of an indication of a too-large firing pin hole or a too small diameter firing pin where it goes through the hole. Can also happen if the hole is chamfered. Or can be a pressure sign (on top of the aforementioned causes.) Can cause primers to "blank", where the crater gets bad enough that primer fails and the little cratered disk blows out (and gets into the bolt/action and causes all kinds of wonky stuff.)

Ejector/extractor marks on case head: These will show up as raised areas on the case, possibly with "wipe" or "smearing" of the mark from when the bolt turns and shaves off part of the raised imprint. Caused by the head being forced against the breech hard enough to get the brass to flow into unsupported areas (ejector hole, extractor cutout.) Usually a sign of pressure, but can be caused by other things as well (excessive shoulder set-back, primarily.)

Case base swelling: Generally a result of high pressure, will cause difficulty in rechambering the fired brass (both before and after normal sizing, as a normal die won't reach low enough on the case to correct it.) Can also be caused by soft brass.

If you are getting gas leakage, blown primers, or failing brass, you are way into the danger zone.

Bottom line is that there really is no definitive pressure sign. Most can be caused by other factors not related (directly) to high pressure. You can use most of the signs above as indicators (especially if you get them in combo), but be aware of the other causes at the same time.




You should. I do. Published data is lawyered down to the point where the data is reasonably sure to be safe in every firearm out there. I very often work a bit above published max (working up to those loads) with no ill effects.

That said, you should still follow the accepted "start low and work up" regimen, as if you go the other way (start at max and work down) you can pretty easily end up breaking stuff (including you.)




Kind of depends on what program.

I like Gordon's Reloading Tool; sort of a poor man's Quickload. Works well for me. I now generally try to stay away from max loads in an effort to maximize brass and firearm life. GRT uses a Max Allowable Pressure - 15% as warning area; I pretty much now load to those specs (though I'm shooting a bolt gun - for auto's you may need more gas to drive the action.)



Not really necessary until you get really consistent at loading ammo (IMO, of course, as are most of my statements.)

To your function problems: Does factory ammo work in your rifle? if it doesn't cycle with factory ammo, you probably won't (safely) correct it with reloads.

If it does work with factory fodder, then slowly working up the charge on your reloads may be in order.

I would, however, suggest loading with a single set of components (powder and bullet) ang get that working before moving to others. Too easy to get confused in results and end up outside of the safe zone (or waste components.) You're not alone in this regard; my shooting buddy does it as well.

Good luck

[Donny1]

would you be able to share the math you are referring to?

With any published data there is are determined values of what a particular charge, barrel length and projectile produce, pressure, fps, fpe. Obviously they won't be the same for every gun even it they are the same as tested, but close.

A baseline of actual conditions is what I'm referring to. Maybe my labeling is incorrect, math, physics or the combination of the two. I am college educated but not in those fields, lol.

I do however have a Bachelors in common sense IMHO.

[Sailormilan2]

Deleted my first post as I misread part of OP’s first post. ��
COL if 2.85” seems a bit long to have a .050” jump. In fact, 2.85” is right at the limit of what will fit into an M14, or AR10, magazine.
What powders and loads are you using?

Edited: I just loaded 2 dummies using Hornady 168 BTHP, which have a similar profile to the Hornady A-Max the OP listed, and loaded to the OP's 2.85". An M14 chambered one fine but the other jammed into the rifling of my PA10. I think the OP needs to recheck his measurements.

[Tommy Gun]

Depending on data you are using, most load data is for Bolt Actions. Honestly when I wanted to load up some 168 SMKs for my AR10 I searched for others recipies and began my ladder loads below and ended a little above those stated recipies. Make sure you use semi auto or AR10 in your search and the post is talk about semi autos. As far as COAL you need to keep magazine OAL in mind as no pint loading further because of what the application is for. I loaded 5 rounds each during my ladders at 2.8 and 2.75 as SAAMI comes more into play in semis.

[sofakingwetodded]

I believe it has to do with bullet length vs the CBTO

I'm currently using winchester 748

[sofakingwetodded]

Depending on data you are using, most load data is for Bolt Actions. Honestly when I wanted to load up some 168 SMKs for my AR10 I searched for others recipies and began my ladder loads below and ended a little above those stated recipies. Make sure you use semi auto or AR10 in your search and the post is talk about semi autos. As far as COAL you need to keep magazine OAL in mind as no pint loading further because of what the application is for. I loaded 5 rounds each during my ladders at 2.8 and 2.75 as SAAMI comes more into play in semis.

I'm able to fit 2.850 in my magazine. I did load at 2.800 but I wanted to reduce the amount of jump.

[sofakingwetodded]

.

I'm not using the A-Max. I'm using the A-tips. No jam at that length. Since I'm reloading at a friend's place, I'll have to go back and get the numbers I recorded for headspace for each bullet

[Sailormilan2]

.

I'm not using the A-Max. I'm using the A-tips. No jam at that length. Since I'm reloading at a friend's place, I'll have to go back and get the numbers I recorded for headspace for each bullet

After my last post I remembered that I had some 168 Hornady A-Max which, which due to their plastic tip are longer. I readjusted the length to OP's length and still got a jammed round in the chamber.

I'm unfamiliar with a Hornady "A-tip". I know they have A-Max, SST, and ELD all with the plastic tip. SSTs are to be loaded shorter than standard.

[sofakingwetodded]

After my last post I remembered that I had some 168 Hornady A-Max which, which due to their plastic tip are longer. I readjusted the length to OP's length and still got a jammed round in the chamber.

I'm unfamiliar with a Hornady "A-tip". I know they have A-Max, SST, and ELD all with the plastic tip. SSTs are to be loaded shorter than standard.

I'm not sure. No jam for me in my 7.62 semi-auto